Biography.com: Euclides of Megara: A life in one paragraph.
Eucleides: Brief biography, from a workstation named after this ancient Greek philosopher.
Euclides: Article from the Internet Encyclopedia of Philosophy, describing this classical thinker's career.
Life of Euclides: From the C.D. Yonge translation of Diogenes Laertius, made available through Peitho's Web.