On this page are sources of ready-information for questions like, when was the protest at Kent State University at which the National Guard opened fire on students?
Use also to confirm information you find in places like Wikipedia: published reference sources go through a more rigorous editing process, so you can rely on the accuracy of the information you find in them.
Finally, reference sources often include bibliographies, making them profitable places to begin a research project.
Bibliographies, handbooks, and guides can assist you in charting a path through the vast amount of research available on a topic. Specialized bibliographies can also help you identify difficult-to-find materials.
These are good, general online sources for biographical information: