Title page of the Encyclopaedia by materialist philosopher Denis Diderot. Image from Credo Reference.
For the student and scholar, reference can have two meaning. One, a source that you can refer to for answers, and also the source, or reference, that accompanies a book or article. A good encyclopedia article gives you the best of both.
For "ready" reference - quick answers or definitions of terms, try Credo Reference.
For more in-depth answers, try the 10 volume Macmillan Encyclopedia of Philosophy, 2nd edition. And if you like that, how about Bioethics, or The New Dictionary of the History of Ideas?
Browse philosophy encyclopedias.
Remember to check the bibliography at the end of an article - a basic trick to build your own bibliography for your paper. Browse the master list of print & electronic encyclopedias available to you as a student for more great sources for your other classes.
Simone de Beauvoir, French existentialist philosopher and author of The Second Sex, wearing an Alexander Calder brooch, circa 1955. Photo from the Hulton Archive/Getty Images. Available in SOLAR.