Zotero

Zotero collects, organises and cites sources. An item is a reference — a book, article, web page, dataset — with its metadata, any attached files, notes and tags. Items go into collections, which are views rather than folders, so one item can sit in several without being duplicated.

Collecting is normally done from the browser. The Zotero Connector extension reads the page you are on, recognises the publisher or catalogue, and saves the metadata and, when it can reach it, the PDF. Metadata can also be retrieved from an ISBN, DOI or arXiv identifier, or by inspecting an existing PDF for those identifiers. Attached PDFs are read and annotated inside Zotero, and highlights flow into notes with the citation already attached.

Citing goes through word processor plugins for LibreOffice Writer, Microsoft Word and Google Docs, which insert live citations and build the bibliography from them. Styles come from the Citation Style Language repository. Libraries sync through zotero.org, with metadata sync separate from file storage, and group libraries let several people share one collection.