Bostock, John. "Natural History". Perseus. Tufts University. Diakses tanggal 23 March 2017. "But it was Apelles of Cos, in the hundred and twelfth Olympiad, who surpassed all the other painters who either preceded or succeeded him. Single-handed, he contributed more to painting than all the others together, and even went so far as to publish some treatises on the principles of the art."
