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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group Juha Hakala 3 Internet-Draft Helsinki University Library 4 Category: Informational 3 July 2002 5 draft-hakala-sici-01.txt 6 Expires: 3 January 2003 8 Using Serial Item and Contribution Identifiers as 9 Uniform Resource Names 11 Status of this Memo 13 This document is an Internet-Draft and is in full conformance with all 14 provisions of Section 10 of RFC2026. 16 Internet-Drafts are working documents of the Internet Engineering Task 17 Force (IETF), its areas, and its working groups. Note that other groups 18 may also distribute working documents as Internet-Drafts. 20 Internet-Drafts are draft documents valid for a maximum of six months 21 and may be updated, replaced, or obsoleted by other documents at any 22 time. It is inappropriate to use Internet-Drafts as reference material 23 or to cite them other than as "work in progress." 25 To view the entire list of Internet-Draft Shadow Directories, see 26 http://www.ietf.org/shadow.html. 28 This Internet-Draft will expire on 3 January 2003. 30 Abstract 32 This document discusses how Serial Item and Contribution Identifiers 33 (SICIs; persistent and unique identifiers for serial issues and 34 contributions such as articles) can be supported within the URN 35 framework and the syntax for URNs defined in RFC 2141 [Moats]. Much of 36 the discussion below is based on the ideas expressed in RFC 2288 37 [Lynch]. Chapter 5 contains a URN namespace registration request 38 modelled according to the template in RFC 2611 [Daigle et al.]. 40 1. Introduction 42 As part of the validation process for the development of URNs the IETF 43 working group agreed that it is important to demonstrate that the 44 current URN syntax proposal can accommodate existing identifiers from 45 well-established namespaces. One such infrastructure for assigning and 46 managing names comes from the bibliographic community. Bibliographic 47 identifiers function as names for objects that exist both in print and, 48 increasingly, in electronic formats. RFC 2288 [Lynch et. al.] 49 investigated the feasibility of using three identifiers (ISBN, ISSN and 50 SICI) as URNs. 52 SICI is an American national standard defined by NISO/ANSI Z39.56-1996 53 [NISO]. The need to develop a new version of the standard is at present 54 being investigated by NISO. 56 RFC 2288 does not � and it was not the aim of its authors � to analyse 57 how SICI-based URNs can actually be resolved. This text will specify one 58 solution to this question. There may be other, complementary resolution 59 services, in addition to the one described here. 61 Generally, the difficulty of designing a URN resolution service is 62 dependent on two factors: 64 * Is the identifier dumb, or does it provide a hint on where to find a 65 resolution service? 67 * How many potential resolution services are there? 69 ISBN (International Standard Book Number) is a good example of an 70 intelligent identifier. Analysis of the ISBN will reveal not only the 71 region where the ISBN has been assigned, but also the publisher of the 72 book. Resolution of ISBN-based URNs can be decentralised to national 73 bibliography databases, maintained by the national libraries. If the 74 ISBN were a dumb identifier, this would be impossible. 76 International Standard Serial Number (ISSN) is a dumb identifier. It 77 does not have a publisher identifier; serials published by a certain 78 company get seemingly random ISSNs. Although ISSNs are allocated to 79 regional agencies in blocks, which gives the system some "intelligence", 80 a resolution service should not rely on these blocks � there are just 81 too many of them, and their number is increasing all the time -, but use 82 the global ISSN database. It contains a bibliographic description of 83 every periodical that has received an ISSN; by June 2002 the database 84 contained about one million bibliographic records. Thus, it is easy to 85 resolve ISSN-based URNs even though the identifier itself does not help 86 in localising the resolution service. 88 SICI is based on ISSN (see below for a description of its syntax). Like 89 ISSN, it is therefore a dumb identifier. But there is not, and will 90 never be, a global SICI database, which would contain bibliographic 91 information about every serial issue and/or article published in the 92 world. Most articles will not be catalogued at all, and the existing 93 bibliographic information about articles is dispersed into a large 94 number of databases maintained by publishers, libraries and other 95 information intermediaries. Although it might be technically possible to 96 merge records from these databases into a union catalogue, in practice 97 such an enterprise is not politically possible. 99 As a "dumb" identifier with a large and ever growing number of potential 100 resolution services SICI poses interesting challenges to the design of 101 the URN resolution process. 103 Generally, a combination of dumb identifier and multiple potential 104 resolution services is a problem, since there is no simple way of 105 finding out which resolution service is the correct one. A gateway 106 service is needed for providing this valuable information. Below we 107 propose that for SICI-based URNs, the global ISSN database could act as 108 a link between the user and the resolution service. 110 The registration request for acquiring a Namespace Identifier (NID) 111 "SICI" for Serial Item and Contribution Identifiers has been written by 112 Helsinki University Library � The National Library of Finland on behalf 113 of the National Information Standards Organization (NISO). The request 114 is included in chapter 5 of this text. 116 The document at hand is part of a global co-operation of the national 117 libraries to foster identification of electronic documents in general 118 and utilisation of URNs in particular. This work is co-ordinated by a 119 working group established by the Conference of Directors of National 120 Libraries (CDNL), and supported by the Conference of the European 121 National Librarians (CENL) Working Group on Networking Standards. 123 We have used the URN Namespace Identifier "SICI" for the Serial Item and 124 Contribution Identifiers in examples below. 126 2. Identification vs. Resolution 128 As a rule the SICIs identify finite, manageably-sized objects, but these 129 objects may still be large enough so that resolution to a hierarchical 130 system, such as all articles published in a serial issue, is 131 appropriate. 133 The materials identified by a SICI may exist only in printed or other 134 physical form, not electronically. The best that a resolver service will 135 be able to offer in this case is bibliographic data from the database 136 providing resolution services, including information about where the 137 physical resource is stored in the owner institution's holdings. 139 3. Serial Item and Contribution Identifier 141 3.1 Overview 143 The Serial Item and Contribution Identifier (SICI) standard defines a 144 variable length code that provides unique identification of serial items 145 (e.g., issues) and the contributions (e.g., articles) contained in a 146 serial title. SICI is specified in NISO/ANSI Z39.56-1996 [NISO]. Like 147 other NISO standards, the SICI document is available for free in the Web. 149 SICI is based on ISO ISSN (International Standard Serial Number), but 150 augments it extensively. SICI is a combination of three segments, all of 151 which are required: 153 Item segment; the data elements needed to describe the serial item such 154 as serial issue (ISSN, Chronology, Enumeration) 156 Contribution segment, the data elements needed to identify contributions 157 within an item (Location, Title Code) 159 Control segment, the data elements needed to record those administrative 160 elements that determine the validity, version, and format of the SICI 161 code representation. 163 RFC 2288 provides the following example: 165 0015-6914(19960101)157:1<62:KTSW>2.0.TX;2-F 167 The first nine characters are the ISSN identifying the serial title. 168 The second component, in parentheses, is the chronology information 169 giving the date the particular serial issue was published. In this 170 example that date was January 1, 1996. The third component, 157:1, 171 is enumeration information (volume, number) for the particular issue 172 of the serial. These three components comprise the "item segment" of 173 a SICI code. By augmenting the ISSN with the chronology and/or 174 enumeration information, specific issues of the serial can be 175 identified. The next segment, <62:KTSW>, identifies a particular 176 contribution within the issue. In this example we provide the 177 starting page number and a title code constructed from the initial 178 characters of the title. Identifiers assigned to a contribution can 179 be used in the contribution segment if page numbers are 180 inappropriate. The rest of the identifier is the control segment, 181 which includes a check character. Interested readers are encouraged 182 to consult the standard for an explanation of the fields in that 183 segment. 185 SICI can be seen as a logical extension of the ISSN to the items and 186 individual contributions that make up a serial's hierarchical structure. 187 The current version of the SICI does have some limitations; it does not 188 allow identification of subsections of an article such as paragraphs or 189 diagrams. If deemed necessary, the functionality needed for article 190 subsection identification could be added to the standard. 192 The current version of SICI (version 2, 1996) guarantees uniqueness in 193 most situations; however, the standard does not always differentiate 194 between multiple variant formats in which an electronic article may be 195 published. For instance, variants of a digitised article published in 196 PDF and HTML formats will receive the same SICI, provided that the ISSN 197 is the same. There are plans to revise the standard; the new version may 198 go further in allowing separation of different versions of an article 199 from one another. 201 According to the rules of the ISSN centre, ISSN numbers can be applied 202 retrospectively to old periodicals. If the original printed document has 203 an ISSN, the same identifier is also valid for the digitised version. 204 ISSN guidelines formulate this principle in the following way: 206 A reproduction is a copy of an item and intended to function as a 207 substitute for that item. The reproduction may be in a different medium 208 from the original but it is not a different edition in itself. The ISSN 209 assigned to the original is valid for the reproduction, a new ISSN is not 210 assigned to the reproduction. 212 ISSN numbers are assigned by regional agencies, which receive ISSN 213 blocks from the ISSN International Centre. SICI usage is not dependent 214 on such formal agencies; the aim is that once ISSN is known, SICI codes 215 can be created by publishers, libraries, document delivery services or 216 even by individual users, either manually or (preferably) by computer 217 program. 219 Given the complexity of SICI codes, the recommended practice is to 220 automate the SICI creation process. If an article is structured enough, 221 all elements of SICI can be extracted from the document. A tool capable 222 of this has been built by the E.U. project DIEPER; this tool, of course, 223 only works properly if the document is structured in the way the DIEPER 224 project recommends. Another, less challenging option is a SICI 225 generator, which builds syntactically correct SICIs, including the check 226 character, if the basic ingredients are typed in manually. 228 3.2 Encoding Considerations and Lexical Equivalence 230 RFC 2288 contains the following simple and yet sufficient analysis of 231 SICI encoding: 233 The character set for SICIs is intended to be email-transport- 234 transparent, so it does not present major problems. However, all 235 printable excluded and reserved characters from the URN syntax are 236 valid in the SICI character set and must be %-encoded. 238 Example of a SICI for an issue of a journal: 240 URN:SICI:1046-8188(199501)13:1%3C%3E1.0.TX;2-F 242 For an article contained within that issue: 244 URN:SICI:1046-8188(199501)13:1%3C69:FTTHBI%3E2.0.TX;2-4 246 Equivalence rules for SICIs are not appropriate for definition as 247 part of the namespace and incorporation in areas such as cache 248 management algorithms. It is best left to resolver systems, which try 249 to determine if two SICIs refer to the same content. Consequently, 250 we do not propose any specific rules for equivalence testing through 251 lexical manipulation. 253 3.3 Resolution of SICI-based URNs 255 Since ISSN is a dumb code, SICI does not contain any explicit hint on 256 where to find the URN resolution service or services. However, an 257 efficient and global resolution service can be accomplished by using the 258 ISSN register as a way station. In June 2002, the ISSN register 259 contained more than one million bibliographic records describing 260 serials, including many thousands of electronic journals. There are 261 several other databases, which contain hundreds of thousands of serial 262 records, but the ISSN register has the best global coverage since the 263 ISSN network covers more than 70 countries. 265 The first step in resolving a SICI-based URN is a query to the ISSN 266 register. The SICI resolution service in the ISSN register will parse 267 the SICI code in order to extract the ISSN from it. 269 ISSN will then be used as a search key for retrieving the bibliographic 270 record of the serial from the ISSN register. 272 Currently the ISSN register already contains thousands of records 273 describing electronic journals. These records contain the URL of the 274 serial's home page. 276 This URL is appropriate for resolving the URN based on the ISSN of the 277 periodical. The mechanism for resolving such URNs via the ISSN register 278 has been specified in the RFC 3044 [Rozenfeld]. The ISSN International 279 Centre has built in 2001 a demonstration URN resolution service for 280 ISSN-based URNs into their present information system, which will be 281 replaced by a new integrated library system in 2003. 283 In order to resolve SICI-based URNs, a new data element has to be added 284 into the bibliographic records in the ISSN register, or elsewhere in 285 this database. This data element would contain the network address (URL) 286 of the system (abstracting and indexing service), which holds the 287 article required and/or bibliographic information about it. It must also 288 be possible to specify volumes and if necessary issues which are 289 included in the system. For example, one A & I �service might contain 290 volumes 1-50, while there is another system holding volumes 25-60. The 291 data element should be repeatable, since the same article may be 292 available from multiple sources. For instance, the publisher, Library of 293 Congress (http://www.loc.gov/), JSTOR (http://www.jstor.org/) and a 294 number of host services such as EBSCO (http://www.ebsco.com/home/) may 295 all have a copy of the same resource. 297 Encoding the holdings data may be non-trivial, since this data is often 298 highly volatile. So, although there are quite a few stable systems such 299 as JSTOR, which can easily be encoded into the ISSN register, full 300 coverage of A & I system will be unlikely. 302 The SICI resolution service built into the ISSN register will check if 303 database address information is available in the bibliographic record of 304 the serial. As the next step, it can make sure that the volume and/or 305 issue needed is available via the target service. If this is the case, 306 the application will make the query, receive the result � article or 307 bibliographic information about it - and pass it on to the user. 309 The functionality described above was implemented in co-operation 310 between the ISSN International Centre and the E.U. project DIEPER 311 (http://gdz.sub.uni-goettingen.de/dieper/). The SICI resolution service 312 is an extension of the service built for resolving ISSN-based URNs. By 313 March 2001 a demonstrator service via which several of the databases 314 maintained by the project partners could be accessed was released for 315 internal use within the project. The ISSN IC and project partners have 316 been willing to maintain the service also after the formal end of the 317 project. 319 Discussions about adding the new data element into bibliographic records 320 in the ISSN register are as of this writing under way. 322 Please note that the discussion herein applies to SICIs assigned to 323 serial contributions. Since serial items (issues) have seldom been 324 described or digitised as such, a search by serial item SICI will in 325 practice be expanded into retrieval of all contributions (articles) 326 within the serial item (issue) in question. 328 If a resolution service for the resource at hand does not exist, or the 329 user is not authorised to utilise it, he/she may get the bibliographic 330 description of the serial from the ISSN register. 332 3.4 Additional considerations 334 Electronic journals have rapidly become very popular in scientific 335 publishing. The main reasons for this are the emergence of viable 336 business models (e.g. licensing) and the birth of a reliable and 337 efficient delivery mechanism (the Web). 339 New content is being added via two different channels. A significant 340 number of scientific journals are published as electronic versions 341 alongside a printed version. On the other hand, old printed volumes are 342 digitised and made available in electronic form. Digitisation is done by 343 development projects such as DIEPER, established services such as JSTOR, 344 or publishers - for instance Elsevier is digitising retrospectively all 345 volumes of the journals the company has published. 347 Reliable linking of articles to references and bibliographic data about 348 the articles is an important issue. URLs are as of this writing the most 349 common means used for linking, but their reliability is low; average 350 lifetime for a URL is estimated to be two years. 352 A more reliable linking mechanism than URLs is urgently needed. Many 353 scientific publishers are already using Digital Object Identifiers (DOI) 354 for their materials. DOI resolution service is based on Handle system, 355 which is "a comprehensive system for assigning, managing, and resolving 356 persistent identifiers, known as "handles," for digital objects and 357 other resources on the Internet" (see 358 http://www.handle.net/introduction.html). Handles can be used as Uniform 359 Resource Names(URNs). 361 URN is both an identifier and a non-commercial and technically advanced 362 resolution service. Due to the co-operation of the ISSN International 363 Centre the URN resolution service for articles outlined in this Internet 364 standard is global, and can accommodate an unlimited number of article 365 services located anywhere in the world. 367 For instance, in order to establish URN-based links to articles 368 digitised in JSTOR service, a number of steps are necessary. First, each 369 article must be identified by SICI, and these SICIs must be indexed in 370 the JSTOR database. Second, the bibliographic records of JSTOR journals 371 in the ISSN register must all be enriched with a link to the JSTOR 372 search interface and volume/issue information. For instance, the 373 bibliographic record describing the journal "Ecology" must contain the 374 information that volumes 1-77 (1920-1996) are available via JSTOR. This 375 information may be quite volatile, and maintenance of the ISSN register 376 must therefore be frequent and efficient. 378 Apart from the modification of the data, some programming work is also 379 needed. Due to the work done in the DIEPER project, the ISSN register 380 already has the functionality needed for resolving SICI-based URNs. 381 Adding the required functionality into the JSTOR database may or may not 382 be difficult depending on the system architecture. One of the design 383 aims of the URN system was to make building of resolution services easy 384 and it seems that in this respect the designers were successful; in the 385 DIEPER project some partners were able to implement the required 386 functionality quite easily. 388 Since the Web browsers do not yet support URN resolution, the final step 389 in enabling resolution of URN-based SICIs in DIEPER was the installation 391 of the browser plug-in developed by the ISSN International Centre. In 392 the future this step may not be required. 394 For various reasons, one article may be available in several locations. 395 Every article copy may have a different set of users who are allowed 396 access to it. For instance, a copy acquired by a national library via 397 legal deposit may only be available within the library premises. 399 Making the links context sensitive � to provide only those links that 400 "work" for a user - is a challenge. OpenURL framework [Van de Sompel] 401 provides a means for sensitive linking, and may be used to complement 402 URN resolution service (filtering of those A & I -services which are not 403 available to the user). As of this writing OpenURL is rapidly gaining 404 popularity, and there are already a few integrated library systems 405 (MetaLib, Voyager) which support it. The future library system of the 406 ISSN register may support OpenURL usage; this would be useful when the 407 same resource (article) is available from several sources, which have 408 different user population. 410 In their present form the URN resolution services provided via the ISSN 411 register suit best those services, which are available in public domain, 412 and are reasonably stable. Numerous digitisation projects such as DIEPER 413 are currently making printed articles available in the Web in digital 414 form. 416 An additional benefit of coding the needed location and volume 417 information into the ISSN register would be that this database then 418 could also serve as a global registry of serial digitisation efforts. 419 Such a register is acutely needed to avoid duplicate work. 421 Since the number of SICI resolution services will eventually be high, 422 the capacity of the server on which the ISSN register runs and its 423 network connections may become a bottleneck, especially if the articles 424 were delivered to the users via the ISSN server. Setting up mirror sites 425 would in this case be the most efficient means for load control and 426 balancing. Technically the setting up of mirror sites is not difficult. 427 The ISSN register contains approximately a million bibliographic 428 records, and is therefore not a very large database. 430 4. Security Considerations 432 This document proposes means of encoding and using Serial Item and 433 Contribution Identifiers within the URN framework. This document does 434 not discuss resolution except at a generic level; thus questions of 435 secure or authenticated resolution mechanisms in the ISSN register or in 436 actual resolution services are out of scope. This text does not address 437 means of validating the integrity or authenticating the source or 438 provenance of URNs that contain SICIs. Issues regarding intellectual 439 property rights associated with objects identified by the various 440 bibliographic identifiers are also beyond the scope of this document, as 441 are questions about rights to the databases that might be used to 442 construct resolvers. 444 5. Namespace registration 446 URN Namespace ID Registration for the Serial Item and Contribution 447 Identifier (SICI) 449 Namespace ID: 451 SICI 453 SICI is a well-established acronym for Serial Item and Contribution 454 Identifiers; giving this NID for any other system would cause a lot of 455 confusion. 457 This namespace ID has already been used in SICI-based URNs in the E.U. 458 project DIEPER. 460 Registration Information: 462 Version: 1 463 Date: 2002-07-03 465 Declared registrant of the namespace: 467 Name: Patricia Harris 468 E-mail: pharris@niso.org 469 Affiliation: National Information Standards Organisation 470 Address: 4733 Bethesda Avenue, Suite 300, Bethesda, MD 20814 472 Declaration of syntactic structure: 474 Each SICI contains three segments: 476 Item segment; the data elements needed to describe the serial item such 477 as serial issue (ISSN, Chronology, Enumeration) 479 Contribution segment, the data elements needed to identify contributions 480 within an item (Location, Title Code) 482 Control segment, the data elements needed to record those administrative 483 elements that determine the validity, version, and format of the SICI 484 code representation. 486 Example: 488 0015-6914(19960101)157:1<62:KTSW>2.0.TX;2-F 490 SICI codes can be generated and parsed by computer programs. 492 Relevant ancillary documentation: 494 SICI is an American national standard defined by NISO/ANSI Z39.56-1996 495 [NISO2]. A new version of the standard is currently under development. 497 Identifier uniqueness considerations: 499 SICI codes will almost always be unique. Since SICI is based on ISSN, 500 articles from different journals will definitely never get the same 501 SICI. Since enumeration and chronology information must also be given, 502 articles and other contributions published in different volumes and 503 issues will also never get the same SICI. 505 SICIs may not be unique if and only if: 507 If two or more contributions are published on the same page(s) and if 508 they have similar enough titles (the first letter of each word is the 509 same). 511 If in a single issue of an electronic journal (which lacks page numbers) 512 there are two or more contributions with titles similar enough. 514 If there are several technical variants of an electronic serial 515 contribution (multiple formats, multiple resolutions) the current 516 version of SICI will not make any difference between these variants. In 517 this case the intellectual content will usually be the same, but layout 518 will differ from one version to another. 520 In the future the SICI standard may be enhanced in order to diminish the 521 risk of non-unique SICIs. 523 Identifier persistence considerations: 525 Once assigned, SICI will never change. The same SICI will not be used 526 again for other serial items and contributions. 528 Process of identifier assignment: 530 There will not be a national, regional or international agency governing 531 the SICI assignment process. Publishers, libraries or other information 532 intermediaries will create SICIs when needed. The most important 533 prerequisite is that the journal must have an ISSN. 535 Although SICI assignment is decentralised, the national ISSN agencies 536 and the ISSN International Centre may support publishers and other 537 interested parties in SICI implementation. 539 SICI can - and should - be built via automated means. If the source 540 document such as article is sufficiently structured, SICI can be 541 generated without human involvement. Another option is a semi-automated 542 process, in which a human user types in the relevant data elements and 543 the application then builds the code. 545 Process for identifier resolution: 547 Resolution will take place in two steps as defined in chapter 3.3. First 548 the ISSN register is used for finding the location of the resolution 549 service(s) for the serial and volume at hand. Using the linking 550 information stored in the serial's bibliographic record, the correct 551 resolution service is contacted, and the requested resource is delivered 552 to the user. 554 Rules for Lexical Equivalence: 556 We do not propose any specific rules for equivalence testing through 557 lexical manipulation. 559 Conformance with URN Syntax: 561 According to the RFC 2288: 563 The character set for SICIs is intended to be email-transport- 564 transparent, so it does not present major problems. However, all 565 printable excluded and reserved characters from the URN syntax are 566 valid in the SICI character set and must be %-encoded. 568 Example of a SICI for an issue of a journal: 570 URN:SICI:1046-8188(199501)13:1%3C%3E1.0.TX;2-F 572 For an article contained within that issue: 574 URN:SICI:1046-8188(199501)13:1%3C69:FTTHBI%3E2.0.TX;2-4 576 Validation mechanism: 578 Validity of a SICI string can be checked by modulus 37 check digit. 580 Scope: 582 Global. 584 6. References 586 [Daigle et al.]: Daigle, L., van Gulik, D., Iannella, R. & Faltstrom, 587 P.: URN Namespace Definition Mechanisms, RFC2611, June 1999. 589 [Lynch] Lynch, C., Using Existing Bibliographic Identifiers as Uniform 590 Resource Names, RFC 2288, February 1998 592 [Moats] Moats, R., URN Syntax, RFC 2141, May 1997. 594 [NISO] NISO/ANSI Z39.56-1996 Serial Item and Contribution Identifier. 595 Electronic resource, available at http://www.techstreet.com/cgi- 596 bin/pdf/free/152629/z39-56.pdf 598 [Rozenfeld] Rozenfeld, S., Using The ISSN (International Serial Standard 599 Number) as URN (Uniform Resource Names) within an ISSN-URN Namespace, 600 RFC 3044, January 2001. 602 [Van de Sompel] Van de Sompel, Herbert & Beit-Arie, Oren: Open Linking 603 in the Scholarly Information Environment Using the OpenURL Framework. D- 604 Lib Magazine, March 2001. Electronic resource, available at 605 http://www.dlib.org/dlib/march01/vandesompel/03vandesompel.html 607 7. Authors' Address 609 Juha Hakala 610 Helsinki University Library - The National Library of Finland 611 P.O. Box 26 612 FIN-00014 Helsinki University 613 FINLAND 615 E-mail: juha.hakala@helsinki.fi 617 8. Full Copyright Statement 619 Copyright (C) The Internet Society (2002). All Rights Reserved. 621 This document and translations of it may be copied and furnished to 622 others, and derivative works that comment on or otherwise explain it 623 or assist in its implementation may be prepared, copied, published 624 and distributed, in whole or in part, without restriction of any 625 kind, provided that the above copyright notice and this paragraph are 626 included on all such copies and derivative works. However, this 627 document itself may not be modified in any way, such as by removing 628 the copyright notice or references to the Internet Society or other 629 Internet organizations, except as needed for the purpose of 630 developing Internet standards in which case the procedures for 631 copyrights defined in the Internet Standards process must be 632 followed, or as required to translate it into languages other than 633 English. 635 The limited permissions granted above are perpetual and will not be 636 revoked by the Internet Society or its successors or assigns. 638 This document and the information contained herein is provided on an 639 "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING 640 TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING 641 BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION 642 HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF 643 MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.