Internet Encyclopedia of Philosophy
Internet Encyclopedia of Philosophy: Diogenes
An extensive biography of Diogenes, his travels, and beliefs.
Other
Diogenes the Ascetic
Discusses the beliefs of Diogenes regarding wealth and pleasure and said he carried Cynicism to the extreme.
Other
Zeno of Citium: Founder of Stoicism
A biography of Zeno, founder of Stoicism. Also discusses the theories of Stoicism. Included a nice set of quotes from Zeno, passed on through other ancient authors.