Academia.edu - Academia is a website where you can share papers that are written with other users. You can use a Google or Facebook account to sign in to the website.
Haihaisoft PDF Reader - Haihaisoft PDF Reader is the name of a free to use PDF reader and printer that is extremely simple to launch.
Mendeley - Easily organize your papers, read & annotate your PDFs, collaborate in private or open groups, and securely access your research from everywhere.
eXPert PDF Reader - eXPert PDF Reader is a free to use PDF reader and views for the Windows operating systems.
Zotero - Zotero is a free, easy-to-use tool to help you collect, organize, cite, and share research.
Flipping PDF Reader - Replace the standard Adobe PDF Reader with the nice flip book. The Flipping PDF Reader allows to read PDF documents in user friendly interface with flipping book effect.