Mendeley is a free reference manager and academic social network that can help you organize your research, collaborate with others online, and discover the latest research
Zotero is a free, open-source citation tool that works with Chrome and Firefox. It allows you to collect organize, cite, and share research.
Docear is a unique solution to academic literature management, i.e. it helps you organizing, creating, and discovering academic literature. Docear is a free tool and is available for Windows, Mac, and Linux.
Citationsy lives in the cloud and is accessible from anywhere. Use our iPhone and Android apps to cite books. Your citation data is saved in the cloud and backed up every 10 minutes.