==== [citation needed] ====
  * online > http://citeulike.com
  * reference > http://citeseerx.ist.psu.edu
  * format > http://www.bibtex.org/ 

==== software ====
  * http://bibdesk.sourceforge.net/
  * firefox plugin > http://www.zotero.org/
  * comparison > [[wp>Comparison_of_reference_management_software]]