For Linux, OS X, and Windows: http://www.zotero.org/ http://www.zotero.org/ http://www.colwiz.com/ http://www.colwiz.com/ For OS X and Windows: http://endno

For Linux, OS X, and Windows: http://www.zotero.org/ http://www.zotero.org/ http://www.colwiz.com/ http://www.colwiz.com/ For OS X and Windows: http://endnote.com/ http://endnote.com/ http://www.mekentosj.com/papers/ http://www.mekentosj.com/papers/ http://pdfstacks.com/ http://pdfstacks.com/ For OS X: http://bibdesk.sourceforge.net/ http://bibdesk.sourceforge.net/ http://www.sonnysoftware.com/bookends/bookends.html http://www.sonnysoftware.com/bookends/bookends.html http://www.thirdstreetsoftware.com/site/SenteForMac.html http://www.thirdstreetsoftware.com/site/SenteForMac.html http://www.ironicsoftware.com/yep/ http://www.ironicsoftware.com/yep/ For Windows: http://www.biblioscape.com/ http://www.biblioscape.com/ http://www.citavi.com/ http://www.citavi.com/ http://www.qiqqa.com/ http://www.qiqqa.com/