Other
Archaeology.info: Australopithecus Robustus
This Archaeology.Info site contains information on the Australopithecus Robustus. This site also includes an extensive section on diagnostic features and references.
Talk Origins Archive
Talk Origins: The Hominid Species
Talk Origins gives a broad description of the types of Hominid species, and then gives a description of each species. Includes the specific characteristics of each, and explains the differences between the species.