internet archive is a non-profit digital library offering free universal access to texts, movies & music, as well as 624 billion archived web pages.

automatic works cited and bibliography formatting for mla, apa and chicago/turabian citation styles. now supports mla 9.

citation machine® helps students and professionals properly credit the information that they use. cite sources in apa, mla, chicago, turabian, and harvard for free.

NSF's mission is to advance the progress of science, a mission accomplished by funding proposals for research and education made by scientists, engineers, and educators from across the country.

zotero is a free, easy-to-use tool to help you collect, organize, cite, and share research.

broken links are everywhere. perma helps authors and journals create permanent links for citations in their published work.