Cicero. De Natura Deorum.

Erasmus, Desiderius. Apophthegmata (1536).

Pliny the Elder. Naturalis Historia.

Plutarch. The Lives of the Noble Grecians and Romans. Trans. Thomas North (1595). 'The Life of Alexander.'

REFERENCE : G.K. Hunter and David Bevington, eds. 'Campaspe' and 'Sappho and Phao.' Manchester: Manchester University Press, 1991. 5-16.