Best Free Bibliographic Database Software (Stub only)

What freeware alternatives are there to the expensive paid bibliographic software (Reference Manager, Endnote etc) now virtually monopolized by Thompsons? 

Note: This bibliographic freeware list is just a stub. Please help us improve it by making suggestions or leaving feedback in the comments. Or why not write a review for this section by joining our site as a volunteer category editor? 

 Standalone  programs:

- Aigaion allows you to categorize publications in your own, user-created topic tree  (Open Source GPL) 

- Bibus is designed for OpenOffice (Open Source GPL) 

- Connotea from Nature Publishing Group is intended for scientists and allows tagging (Open Source GPL) 

- JabRef provides a user interface for editing reference lists filed in BibTex format only (Open Source GPL) 

- Jumper 2.0 is an Enterprise Bookmarking engine designed for organizations - it provides "a web-infrastructure platform for tagging and linking data objects"  (Open Source GPL)

- Mendeley "desktop and web solution designed for managing and sharing research papers, discovering research data and collaborating online" -  supports OpenOffice (freeware, proprietary beta)

- Refbase is a web-based, multi-user interface for managing scientific literature & citations in various formats (Open Source GPL)

- RefDB is a reference database tool (for SGML, XML, and LaTeX/BibTeX documents) which allows network sharing  (Open Source GPL)

Web apps

 - I, Librarian is a PHP program for creating annotated (SQLite) collections of PDFs  (Open Source GPL; Windows, Linux only)

- JabRef (see above) can also be used as a web app.

- Mendeley (see above) appears to be primarily envisaged as a web app.

- WIKINDX is a single/multi-user bibliographic and quotations/notes management and article authoring system (Open Source GPL).

- RefDB (see above) also allows read-only access via a web browser.

- Zotero is a Firefox extension designed to gather research info from the internet, which can also perform some reference management functions  (Open Source GPL).

Two useful sources of information are:

• Wikipedia comparison of reference management software with links to the available apps (both freeware and $ware) and tables containing invaluable compatibility information. 

• Wordpress comparison of free bibliographic managers

[This article is about: free bibliography software, bibliographic reference database management freeware]