Licenses and credits

Last updated November 5, 2026

Citation styles

The citation generator uses citation style and locale files from the Citation Style Language project (styles, locales), licensed under CC BY-SA 3.0. Styles used: APA 7th edition, MLA Handbook 9th edition, Chicago Manual of Style 17th edition (author-date; notes and bibliography), Cite Them Right 12th edition (Harvard) and IEEE. Credit to their authors and contributors as listed in each style file.

Citation formatting engine

Word lists

Automatic APA sentence case uses the 20,000 most frequent English words from wordfreq (data © Robyn Speer, CC BY-SA 4.0) that appear in lowercase in SCOWL (Copyright 2000–2018 Kevin Atkinson; permission to use, copy, modify, distribute and sell granted provided the copyright notice appears in all copies).

File upload

Text is read from uploaded PDF files with pypdfium2 (© pypdfium2 contributors, Apache License 2.0 / BSD 3-Clause) and PDFium (© The PDFium Authors, BSD 3-Clause), which includes FreeType (portions of this software are copyright © The FreeType Project, www.freetype.org, used under the FreeType License), libjpeg-turbo (this software is based in part on the work of the Independent JPEG Group), OpenJPEG, libpng, zlib, Little CMS, ICU, Abseil, AGG, fast_float, simdutf and LLVM libc, each under its own permissive licence. DOCX files are read with Mammoth (© Michael Williamson, BSD 2-Clause), with Mammoth's dependencies JSZip (MIT licence chosen from its MIT/GPL dual licence), pako (MIT and Zlib), @xmldom/xmldom (MIT), underscore (MIT), lop, option and dingbat-to-unicode (BSD 2-Clause), base64-js, xmlbuilder, lie, immediate, setimmediate and readable-stream (MIT). Files are read in memory and not stored.

Zotero translation-server

Source details are read with the Zotero translation-server and the Zotero translators (© Corporation for Digital Scholarship and contributors, GNU Affero General Public License v3.0). We run it unmodified as a separate service. Source code of the version we run: translation-server 672d4f3 with translators 9d04f4b.

Bibliographic data

When that service has no answer, source details are looked up from Crossref, the Library of Congress catalogue (SRU, MODS), the K10plus union catalogue of GBV and SWB (SRU, MARC 21), Open Library and the pages you link to. The order of the book catalogues and the field mapping follow the approach of the Zotero translators (no code was copied). Always check a citation against the source before you use it.