Stanford University
Stanford Encyclopedia of Philosophy: Stoic Logic
An extensive discussion of the Stoic beliefs about logic, their advancements in the field of logic, the arguments of the Skeptics and the answers of the Stoics
Steven Kreis, PhD
The History Guide: From Polis to Cosmopolis
A great overview of the world of Alexander the Great, beginning with the military exploits of his father, Philip of Macedon. Included is a look at Hellenistic philosophies.
Other
The Ecole Initiative: Stoicism
This site from the University of Evansville provides an extensive look at Stoicism, its background, and the philosophers who influenced this philosophy. Very in-depth and informative, with great information.