Zotero - Zotero is a free, easy-to-use tool to help you collect, organize, cite, and share research.
Qiqqa - Qiqqa is a free research and reference management software. It can be used in many organizational projects from the academic to the personal to the business endeavor. Read more about Qiqqa.
Diigo - Diigo is a powerful research tool and a knowledge-sharing community
JabRef - Graphical Java application for managing bibtex (. bib) databases.JabRef · JabRef Help · JabRef | Blog · OpenOffice/LibreOffice .
Weava - Workspace to highlight, organize & collaborate on your research articles.
Citavi - Citavi is a program for Microsoft Windows that manages literary references and organizes organizational knowledge.