Find two open source software for organizing research papers and their BibTex entries, one uses Perl: Document Archive, and another uses PHP: Document Database. Since I am more familiar with PHP, I will try the latter one day. Feather list of Document Database:

* User Account Management with groups for Admins and Users
* Entry of any current BibTeX Document type with context sensitive help function
* Simple search within any single or all fields
* Boolean Search with Query Builder (1.2)
* Last viewed list
* Emulates BibTeX layout for easy verification including limited support for foreign characters (1.2)
* Uploads of documents (read the Disclaimer)
* Uploads of files into a searchable filearea (1.2)
* BibTeX output for each entry
* User can share notes on documents (1.2)
* Supports multiple instances on the same machine (1.0.1)
* Robust and easy installation (1.0.1)

via: Zhangqi Yin