Aigaion Reference Management System - Aigaion is a bibliography management system that seems to be the perfect tool for managing your bibliography and references.

BibBase - BibBase.org is an easy way to set up and maintain a scientific publications page.

ProCite - ProCite is a tool for creating citations according to the standard defined by the users.

I Librarian - I Librarian is an online tool that comes with a great way to handle and manage your PDF paper and office documents.

Papers by ReadCube - ReadCube Papers is a sumptuous reference manager helping out academic writers to get the most out when it comes to access and discovering more citations with multiple libraries or databases.

Mendeley - Easily organize your papers, read & annotate your PDFs, collaborate in private or open groups, and securely access your research from everywhere.