Wiktionary (English Wikipedia)

Analysis of information sources in references of the Wikipedia article "Wiktionary" in English language version.

refsWebsite

Global rank English rank

27web.archive.org

1^st place

11wikimedia.org

low place

8wiktionary.org

649^th place

827^th place

5aksw.org

low place

5tu-darmstadt.de

low place

3uka.de

low place

2mediawiki.org

low place

9,522^nd place

2wikimedia.de

low place

2arxiv.org

69^th place

59^th place

2aclweb.org

low place

6,793^rd place

1uni-leipzig.de

2,676^th place

5,949^th place

1wikipedia.org

low place

1netls.org

low place

1code.google.com

4,942^nd place

4,061^st place

1newyorker.com

146^th place

110^th place

1acm.org

1,185^th place

840^th place

1proquest.com

206^th place

124^th place

1worldcat.org

5^th place

1dbpedia.org

8,726^th place

low place

1dkpro.github.io

low place

1github.com

383^rd place

320^th place

1psu.edu

207^th place

136^th place

1doi.org

2^nd place

1semanticscholar.org

11^th place

8^th place

1demelo.org

low place

1mt-archive.info

low place

1mit.edu

415^th place

327^th place

1harvard.edu

18^th place

17^th place

1bham.ac.uk

6,934^th place

4,192^nd place

1aaai.org

9,352^nd place

5,696^th place

1wikidata.org

43^rd place

161^st place

aaai.org

Chesley et al. 2006. Chesley, Paula; Vincent, Bruce; Xu, Li; Srihari, Rohini K. (2006). "Using verbs and adjectives to automatically classify blog sentiment" (PDF). Training. 580: 233–235. Archived from the original (PDF) on February 24, 2021. Retrieved May 9, 2013.

aclweb.org

McFate & Forbus 2011. McFate, Clifton J.; Forbus, Kenneth D. (2011). "NULEX: an open-license broad coverage lexicon" (PDF). The 49th Annual Meeting of the Association for Computational Linguistics: Human Language Technologies, Proceedings of the Conference. Portland, Oregon, USA: The Association for Computer Linguistics. pp. 363–367. ISBN 978-1-932432-88-6.

newdesign.aclweb.org

Li, Graça & Taskar 2012. Li, Shen; Graça, Joao V.; Taskar, Ben (2012). "Wiki-ly supervised part-of-speech tagging" (PDF). Proceedings of the 2012 Joint Conference on Empirical Methods in Natural Language Processing and Computational Natural Language Learning. Jeju Island, Korea: Association for Computational Linguistics. pp. 1389–1398. Archived from the original (PDF) on May 22, 2013. Retrieved May 10, 2013.

acm.org

portal.acm.org

Kurmas 2010. Kurmas, Zachary (July 2010). Zawilinski: a library for studying grammar in Wiktionary. Proceedings of the 6th International Symposium on Wikis and Open Collaboration. Gdansk, Poland. Retrieved July 29, 2011.

aksw.org

svn.aksw.org

Hellmann & Auer 2013, p. 302, p. 16 in PDF. Hellmann, S.; Auer, S. (2013). "Towards Web-Scale Collaborative Knowledge Extraction" (PDF). In Gurevych, Iryna; Kim, Jungi (eds.). The People's Web Meets NLP. Theory and Applications of Natural Language Processing. Springer-Verlag. pp. 287–313. ISBN 978-3-642-35084-9. Archived (PDF) from the original on October 27, 2014. Retrieved May 10, 2013.
Hellmann, Brekle & Auer 2012, p. 3, Table 1. Hellmann, Sebastian; Brekle, Jonas; Auer, Sören (2012). "Leveraging the Crowdsourcing of Lexical Resources for Bootstrapping a Linguistic Data Cloud" (PDF). Proc. Joint Int. Semantic Technology Conference (JIST). Nara, Japan.
Hellmann, Brekle & Auer 2012, pp. 8–9. Hellmann, Sebastian; Brekle, Jonas; Auer, Sören (2012). "Leveraging the Crowdsourcing of Lexical Resources for Bootstrapping a Linguistic Data Cloud" (PDF). Proc. Joint Int. Semantic Technology Conference (JIST). Nara, Japan.
Hellmann, Brekle & Auer 2012, p. 10. Hellmann, Sebastian; Brekle, Jonas; Auer, Sören (2012). "Leveraging the Crowdsourcing of Lexical Resources for Bootstrapping a Linguistic Data Cloud" (PDF). Proc. Joint Int. Semantic Technology Conference (JIST). Nara, Japan.
Hellmann, Brekle & Auer 2012, p. 11. Hellmann, Sebastian; Brekle, Jonas; Auer, Sören (2012). "Leveraging the Crowdsourcing of Lexical Resources for Bootstrapping a Linguistic Data Cloud" (PDF). Proc. Joint Int. Semantic Technology Conference (JIST). Nara, Japan.

arxiv.org

Smirnov et al. 2012. Smirnov A, Levashova T, Karpov A, Kipyatkova I, Ronzhin A, Krizhanovsky A, Krizhanovsky N (2012). "Analysis of the quotation corpus of the Russian Wiktionary". Research in Computing Science. 56: 101–112. arXiv:2002.00734. CiteSeerX 10.1.1.694.9627. doi:10.13053/rcs-56-1-11 (inactive September 17, 2024). S2CID 10726045.{{cite journal}}: CS1 maint: DOI inactive as of September 2024 (link)
Lin & Krizhanovsky 2011. Lin, Feiyu; Krizhanovsky, Andrew (2011). "Multilingual ontology matching based on Wiktionary data accessible via SPARQL endpoint". Proc. of the 13th Russian Conference on Digital Libraries RCDL'2011. Voronezh, Russia. pp. 19–26. arXiv:1109.0732. Bibcode:2011arXiv1109.0732L.

bham.ac.uk

eee.bham.ac.uk

Medero & Ostendorf 2009. Medero, Julie; Ostendorf, Mari (2009). "Analysis of vocabulary difficulty using wiktionary" (PDF). Proc. SLaTE Workshop. Archived from the original (PDF) on April 24, 2014. Retrieved May 10, 2013.

code.google.com

The source code and the results of POS-tagging are available at https://code.google.com/p/wikily-supervised-pos-tagger

dbpedia.org

"DBpedia Wiktionary". Archived from the original on May 4, 2013.

demelo.org

gerard.demelo.org

"Gerard de Melo's Research at ICSI, Berkeley". gerard.demelo.org. Archived from the original on March 27, 2023. Retrieved March 6, 2023.

dkpro.github.io

"Welcome". DKPro JWKTL. Archived from the original on January 23, 2021. Retrieved June 23, 2019.

doi.org

Smirnov et al. 2012. Smirnov A, Levashova T, Karpov A, Kipyatkova I, Ronzhin A, Krizhanovsky A, Krizhanovsky N (2012). "Analysis of the quotation corpus of the Russian Wiktionary". Research in Computing Science. 56: 101–112. arXiv:2002.00734. CiteSeerX 10.1.1.694.9627. doi:10.13053/rcs-56-1-11 (inactive September 17, 2024). S2CID 10726045.{{cite journal}}: CS1 maint: DOI inactive as of September 2024 (link)

github.com

"Wikokit - Machine-readable Wiktionary". December 19, 2022. Archived from the original on October 2, 2020. Retrieved November 7, 2015 – via GitHub.

harvard.edu

ui.adsabs.harvard.edu

Lin & Krizhanovsky 2011. Lin, Feiyu; Krizhanovsky, Andrew (2011). "Multilingual ontology matching based on Wiktionary data accessible via SPARQL endpoint". Proc. of the 13th Russian Conference on Digital Libraries RCDL'2011. Voronezh, Russia. pp. 19–26. arXiv:1109.0732. Bibcode:2011arXiv1109.0732L.

mediawiki.org

Wikimedia's MediaWiki API:Sitematrix. Retrieved September 2024 from Data:Wikipedia statistics/meta.tab
Wikimedia's MediaWiki API:Siteinfo. Retrieved September 2024 from Data:Wikipedia statistics/data.tab

mit.edu

conceptnet5.media.mit.edu

"ConceptNet 5". conceptnet5.media.mit.edu. Archived from the original on October 19, 2011. Retrieved September 23, 2023.

mt-archive.info

Otte & Tyers 2011. Otte, Pim; Tyers, F. M. (2011). "Rapid rule-based machine translation between Dutch and Afrikaans" (PDF). In Forcada, Mikel L.; Depraetere, Heidi; Vandeghinste, Vincent (eds.). 16th Annual Conference of the European Association of Machine Translation, EAMT11. Leuven, Belgium. pp. 153–160. Archived from the original (PDF) on February 25, 2021. Retrieved May 10, 2013.

netls.org

In this citation, the author refers to Wiktionary as part of the Wikipedia site: Adapted from an article by Naomi DeTullio (2006). "Wikis for Librarians" (PDF). NETLS News #142. Northeast Texas Library System. p. 15. Archived from the original (PDF newsletter) on June 5, 2007. Retrieved April 21, 2007.

newyorker.com

Lepore 2006. Lepore, Jill (November 6, 2006). "Noah's Ark". The New Yorker (Abstract). Retrieved April 21, 2007.

proquest.com

Sascha & Müller-Spitzer 2016, p. 348 Sascha, Wolfer; Müller-Spitzer, Carolin (2016). "How Many People Constitute a Crowd and What Do They Do? Quantitative Analyses of Revisions in the English and German Wiktionary Editions". Lexikos. 26: 347–371. ISSN 1684-4904. OCLC 7211535994. Archived from the original on May 9, 2023. Retrieved August 27, 2021 – via ProQuest.

psu.edu

citeseerx.ist.psu.edu

Smirnov et al. 2012. Smirnov A, Levashova T, Karpov A, Kipyatkova I, Ronzhin A, Krizhanovsky A, Krizhanovsky N (2012). "Analysis of the quotation corpus of the Russian Wiktionary". Research in Computing Science. 56: 101–112. arXiv:2002.00734. CiteSeerX 10.1.1.694.9627. doi:10.13053/rcs-56-1-11 (inactive September 17, 2024). S2CID 10726045.{{cite journal}}: CS1 maint: DOI inactive as of September 2024 (link)

semanticscholar.org

api.semanticscholar.org

Smirnov et al. 2012. Smirnov A, Levashova T, Karpov A, Kipyatkova I, Ronzhin A, Krizhanovsky A, Krizhanovsky N (2012). "Analysis of the quotation corpus of the Russian Wiktionary". Research in Computing Science. 56: 101–112. arXiv:2002.00734. CiteSeerX 10.1.1.694.9627. doi:10.13053/rcs-56-1-11 (inactive September 17, 2024). S2CID 10726045.{{cite journal}}: CS1 maint: DOI inactive as of September 2024 (link)

tu-darmstadt.de

ukp.tu-darmstadt.de

Meyer & Gurevych 2012, p. 140. Meyer, C. M.; Gurevych, I. (2012). "OntoWiktionary – Constructing an Ontology from the Collaborative Online Dictionary Wiktionary" (PDF). In Pazienza, M. T.; Stellato, A. (eds.). Semi-Automatic Ontology Development: Processes and Resources. IGI Global. pp. 131–161. ISBN 978-1-4666-0188-8. Archived from the original (PDF) on October 9, 2013.
Zesch, Müller & Gurevych 2008, p. 4, Figure 1. Zesch, Torsten; Müller, Christof; Gurevych, Iryna (2008). "Extracting Lexical Semantic Knowledge from Wikipedia and Wiktionary" (PDF). Proceedings of the Conference on Language Resources and Evaluation (LREC). Marrakech, Morocco.
Zesch, Müller & Gurevych 2008. Zesch, Torsten; Müller, Christof; Gurevych, Iryna (2008). "Extracting Lexical Semantic Knowledge from Wikipedia and Wiktionary" (PDF). Proceedings of the Conference on Language Resources and Evaluation (LREC). Marrakech, Morocco.
Meyer & Gurevych 2012. Meyer, C. M.; Gurevych, I. (2012). "OntoWiktionary – Constructing an Ontology from the Collaborative Online Dictionary Wiktionary" (PDF). In Pazienza, M. T.; Stellato, A. (eds.). Semi-Automatic Ontology Development: Processes and Resources. IGI Global. pp. 131–161. ISBN 978-1-4666-0188-8. Archived from the original (PDF) on October 9, 2013.

informatik.tu-darmstadt.de

Meyer & Gurevych 2010, p. 40. Meyer, C. M.; Gurevych, I. (2010). "Worth its Weight in Gold or Yet Another Resource - A Comparative Study of Wiktionary, OpenThesaurus and GermaNet" (PDF). Proc. 11th International Conference on Intelligent Text Processing and Computational Linguistics, Iasi, Romania. pp. 38–49. Archived from the original (PDF) on December 1, 2017. Retrieved May 10, 2013.

uka.de

csl.ira.uka.de

Schlippe, Ochs & Schultz 2012. Schlippe, Tim; Ochs, Sebastian; Schultz, Tanja (2012). "Grapheme-to-phoneme model generation for Indo-European languages" (PDF). Acoustics, Speech and Signal Processing (ICASSP). Kyoto, Japan. pp. 4801–4804. Archived from the original (PDF) on October 6, 2014. Retrieved May 10, 2013.
Schlippe, Ochs & Schultz 2012, p. 4802. Schlippe, Tim; Ochs, Sebastian; Schultz, Tanja (2012). "Grapheme-to-phoneme model generation for Indo-European languages" (PDF). Acoustics, Speech and Signal Processing (ICASSP). Kyoto, Japan. pp. 4801–4804. Archived from the original (PDF) on October 6, 2014. Retrieved May 10, 2013.
Schlippe, Ochs & Schultz 2012, p. 4804. Schlippe, Tim; Ochs, Sebastian; Schultz, Tanja (2012). "Grapheme-to-phoneme model generation for Indo-European languages" (PDF). Acoustics, Speech and Signal Processing (ICASSP). Kyoto, Japan. pp. 4801–4804. Archived from the original (PDF) on October 6, 2014. Retrieved May 10, 2013.

uni-leipzig.de

informatik.uni-leipzig.de

Hồ Ngọc Đức, Free Vietnamese Dictionary Project. Details at the Vietnamese Wiktionary.

web.archive.org

In this citation, the author refers to Wiktionary as part of the Wikipedia site: Adapted from an article by Naomi DeTullio (2006). "Wikis for Librarians" (PDF). NETLS News #142. Northeast Texas Library System. p. 15. Archived from the original (PDF newsletter) on June 5, 2007. Retrieved April 21, 2007.
"Wikipedia mailing list archive discussion announcing the opening of the Wiktionary project". December 12, 2002. Archived from the original on June 20, 2014. Retrieved May 3, 2011.
Wikipedia mailing list archive discussion from Larry Sanger giving the idea on Wiktionary Archived June 20, 2014, at the Wayback Machine – Retrieved May 3, 2011
"Wiktionary". www.wiktionary.org. Archived from the original on September 13, 2008. Retrieved October 28, 2021.
TheDaveBot Archived October 11, 2007, at the Wayback Machine, TheCheatBot Archived October 11, 2007, at the Wayback Machine, Websterbot Archived October 11, 2007, at the Wayback Machine, PastBot Archived October 11, 2007, at the Wayback Machine, NanshuBot Archived October 11, 2007, at the Wayback Machine
Detailed statistics Archived July 23, 2021, at the Wayback Machine as of July 21, 2021
"LXbot". Archived from the original on May 24, 2008.
"Wiktionary:Statistics". March 29, 2022. Archived from the original on March 6, 2023. Retrieved March 6, 2023 – via Wiktionary.
"Wiktionary Statistics". Meta.Wikimedia.org. Archived from the original on September 2, 2020. Retrieved September 11, 2020.
Sascha & Müller-Spitzer 2016, p. 348 Sascha, Wolfer; Müller-Spitzer, Carolin (2016). "How Many People Constitute a Crowd and What Do They Do? Quantitative Analyses of Revisions in the English and German Wiktionary Editions". Lexikos. 26: 347–371. ISSN 1684-4904. OCLC 7211535994. Archived from the original on May 9, 2023. Retrieved August 27, 2021 – via ProQuest.
Meyer & Gurevych 2012, p. 140. Meyer, C. M.; Gurevych, I. (2012). "OntoWiktionary – Constructing an Ontology from the Collaborative Online Dictionary Wiktionary" (PDF). In Pazienza, M. T.; Stellato, A. (eds.). Semi-Automatic Ontology Development: Processes and Resources. IGI Global. pp. 131–161. ISBN 978-1-4666-0188-8. Archived from the original (PDF) on October 9, 2013.
Meyer & Gurevych 2010, p. 40. Meyer, C. M.; Gurevych, I. (2010). "Worth its Weight in Gold or Yet Another Resource - A Comparative Study of Wiktionary, OpenThesaurus and GermaNet" (PDF). Proc. 11th International Conference on Intelligent Text Processing and Computational Linguistics, Iasi, Romania. pp. 38–49. Archived from the original (PDF) on December 1, 2017. Retrieved May 10, 2013.
Hellmann & Auer 2013, p. 302, p. 16 in PDF. Hellmann, S.; Auer, S. (2013). "Towards Web-Scale Collaborative Knowledge Extraction" (PDF). In Gurevych, Iryna; Kim, Jungi (eds.). The People's Web Meets NLP. Theory and Applications of Natural Language Processing. Springer-Verlag. pp. 287–313. ISBN 978-3-642-35084-9. Archived (PDF) from the original on October 27, 2014. Retrieved May 10, 2013.
"DBpedia Wiktionary". Archived from the original on May 4, 2013.
"Welcome". DKPro JWKTL. Archived from the original on January 23, 2021. Retrieved June 23, 2019.
"Wikokit - Machine-readable Wiktionary". December 19, 2022. Archived from the original on October 2, 2020. Retrieved November 7, 2015 – via GitHub.
"Gerard de Melo's Research at ICSI, Berkeley". gerard.demelo.org. Archived from the original on March 27, 2023. Retrieved March 6, 2023.
Otte & Tyers 2011. Otte, Pim; Tyers, F. M. (2011). "Rapid rule-based machine translation between Dutch and Afrikaans" (PDF). In Forcada, Mikel L.; Depraetere, Heidi; Vandeghinste, Vincent (eds.). 16th Annual Conference of the European Association of Machine Translation, EAMT11. Leuven, Belgium. pp. 153–160. Archived from the original (PDF) on February 25, 2021. Retrieved May 10, 2013.
Schlippe, Ochs & Schultz 2012. Schlippe, Tim; Ochs, Sebastian; Schultz, Tanja (2012). "Grapheme-to-phoneme model generation for Indo-European languages" (PDF). Acoustics, Speech and Signal Processing (ICASSP). Kyoto, Japan. pp. 4801–4804. Archived from the original (PDF) on October 6, 2014. Retrieved May 10, 2013.
Schlippe, Ochs & Schultz 2012, p. 4802. Schlippe, Tim; Ochs, Sebastian; Schultz, Tanja (2012). "Grapheme-to-phoneme model generation for Indo-European languages" (PDF). Acoustics, Speech and Signal Processing (ICASSP). Kyoto, Japan. pp. 4801–4804. Archived from the original (PDF) on October 6, 2014. Retrieved May 10, 2013.
Schlippe, Ochs & Schultz 2012, p. 4804. Schlippe, Tim; Ochs, Sebastian; Schultz, Tanja (2012). "Grapheme-to-phoneme model generation for Indo-European languages" (PDF). Acoustics, Speech and Signal Processing (ICASSP). Kyoto, Japan. pp. 4801–4804. Archived from the original (PDF) on October 6, 2014. Retrieved May 10, 2013.
Meyer & Gurevych 2012. Meyer, C. M.; Gurevych, I. (2012). "OntoWiktionary – Constructing an Ontology from the Collaborative Online Dictionary Wiktionary" (PDF). In Pazienza, M. T.; Stellato, A. (eds.). Semi-Automatic Ontology Development: Processes and Resources. IGI Global. pp. 131–161. ISBN 978-1-4666-0188-8. Archived from the original (PDF) on October 9, 2013.
"ConceptNet 5". conceptnet5.media.mit.edu. Archived from the original on October 19, 2011. Retrieved September 23, 2023.
Medero & Ostendorf 2009. Medero, Julie; Ostendorf, Mari (2009). "Analysis of vocabulary difficulty using wiktionary" (PDF). Proc. SLaTE Workshop. Archived from the original (PDF) on April 24, 2014. Retrieved May 10, 2013.
Li, Graça & Taskar 2012. Li, Shen; Graça, Joao V.; Taskar, Ben (2012). "Wiki-ly supervised part-of-speech tagging" (PDF). Proceedings of the 2012 Joint Conference on Empirical Methods in Natural Language Processing and Computational Natural Language Learning. Jeju Island, Korea: Association for Computational Linguistics. pp. 1389–1398. Archived from the original (PDF) on May 22, 2013. Retrieved May 10, 2013.
Chesley et al. 2006. Chesley, Paula; Vincent, Bruce; Xu, Li; Srihari, Rohini K. (2006). "Using verbs and adjectives to automatically classify blog sentiment" (PDF). Training. 580: 233–235. Archived from the original (PDF) on February 24, 2021. Retrieved May 9, 2013.
"Wikidata:Wiktionary". Archived from the original on January 3, 2023. Retrieved October 12, 2012.

wikidata.org

"Wikidata:Wiktionary". Archived from the original on January 3, 2023. Retrieved October 12, 2012.

wikimedia.de

tools.wikimedia.de

TheDaveBot Archived October 11, 2007, at the Wayback Machine, TheCheatBot Archived October 11, 2007, at the Wayback Machine, Websterbot Archived October 11, 2007, at the Wayback Machine, PastBot Archived October 11, 2007, at the Wayback Machine, NanshuBot Archived October 11, 2007, at the Wayback Machine
"LXbot". Archived from the original on May 24, 2008.

wikimedia.org

meta.wikimedia.org

Wiktionary total article counts are here. Detailed statistics by word type are available here [1].
"Wiktionary/logo", Meta-Wiki, Wikimedia Foundation.
"Wiktionary/logo/refresh/voting", Meta-Wiki, Wikimedia Foundation.
m:Wiktionary/logo#Logo use statistics.
"Wiktionary Statistics". Meta.Wikimedia.org. Archived from the original on September 2, 2020. Retrieved September 11, 2020.

wikipedia.org

vi.wikipedia.org

Hồ Ngọc Đức, Free Vietnamese Dictionary Project. Details at the Vietnamese Wiktionary.

wiktionary.org

en.wiktionary.org

Wiktionary total article counts are here. Detailed statistics by word type are available here [1].
The user list at the English Wiktionary identifies accounts that have been given "bot status".
E.g. compare the entry structure and formatting rules in English Wiktionary and Russian Wiktionary.
Detailed statistics Archived July 23, 2021, at the Wayback Machine as of July 21, 2021
"Wiktionary:Statistics". March 29, 2022. Archived from the original on March 6, 2023. Retrieved March 6, 2023 – via Wiktionary.
"Wiktionary talk:Wiktionary Logo", English Wiktionary, Wikimedia Foundation.

wiktionary.org

Wiktionary's current URL is www.wiktionary.org
"Wiktionary". www.wiktionary.org. Archived from the original on September 13, 2008. Retrieved October 28, 2021.

worldcat.org

search.worldcat.org

Sascha & Müller-Spitzer 2016, p. 348 Sascha, Wolfer; Müller-Spitzer, Carolin (2016). "How Many People Constitute a Crowd and What Do They Do? Quantitative Analyses of Revisions in the English and German Wiktionary Editions". Lexikos. 26: 347–371. ISSN 1684-4904. OCLC 7211535994. Archived from the original on May 9, 2023. Retrieved August 27, 2021 – via ProQuest.

Wiktionary (English Wikipedia)

aaai.org

aclweb.org

aclweb.org

newdesign.aclweb.org

acm.org

portal.acm.org

aksw.org

svn.aksw.org

arxiv.org

bham.ac.uk

eee.bham.ac.uk

code.google.com

dbpedia.org

demelo.org

gerard.demelo.org

dkpro.github.io

doi.org

github.com

harvard.edu

ui.adsabs.harvard.edu

mediawiki.org

mit.edu

conceptnet5.media.mit.edu

mt-archive.info

netls.org

newyorker.com

proquest.com

psu.edu

citeseerx.ist.psu.edu

semanticscholar.org

api.semanticscholar.org

tu-darmstadt.de

ukp.tu-darmstadt.de

informatik.tu-darmstadt.de

uka.de

csl.ira.uka.de

uni-leipzig.de

informatik.uni-leipzig.de

web.archive.org

wikidata.org

wikimedia.de

tools.wikimedia.de

wikimedia.org

meta.wikimedia.org

lists.wikimedia.org

commons.wikimedia.org

phabricator.wikimedia.org

wikipedia.org

vi.wikipedia.org

wiktionary.org

en.wiktionary.org

wiktionary.org

worldcat.org

search.worldcat.org