Cloister is a Mac OS X application (Objective-C/Cocoa) designed to keep track of technical papers. It allows PDF versions of the papers to be stored alongside their BibTeX information and eases the task of generating and maintaining BibTeX databases and citations for your LaTeX documents.
Conveniently stores PDF documents.
Maintains BibTeX details and abstracts/annotations alongside papers.
Generates BibTeX citations/files easily.
Groups papers according to subject matter, or a paper you're working on.
Imports existing BibTeX entries.
User-friendly interface, very similar to Apple's Address Book application.