Cassius Dio and Ulpian  
   Article by Robert L. Cleve in Ancient History Bulletin on the contrasting accounts of the regency during the reign of Severus Alexander.
   http://www.severusalexander.com/cleve.htm

Dio Cassius (c. A.D. 40 - 110) - Cassius Dio Cocceianus  
   PDF and hypertext selections from the 1914 Cary/Loeb translation of the Roman History.
   http://www.brainfly.net/html/dio_cass.htm

Dio Cassius on Scipio's Return from Spain in 205 B.C.  
   Paper by M. James Moscovich in Ancient History Bulletin 2.5, with notes, criticizing the historicity of Dio's account of the controversy over P. Cornelius Scipio's departure for Rome.
   http://www.barca.fsnet.co.uk/scipio-africanus-return-spain.htm

Dio Cassius  
   Brief biography of Cassius Dio Coccetanus from the 1911 Encyclopedia Britannica.
   http://4.1911encyclopedia.org/D/DI/DIO_CASSIUS.htm

Lacus Curtius: Cassius Dio's Roman History  
   Full text by chapter of the 1914 English translation by Earnest Cary.
   http://penelope.uchicago.edu/Thayer/E/Roman/Texts/Cassius_Dio/home.html

Cassius Dio - Book XXXIX  
   Transcription of Dio's account of Caesar's campaign against the Veneti.
   http://www.ourpasthistory.com/roman%20cassius_dio.htm