APA (7th ed.) Citation

Olmstead, A. T. (1948). A History of the Persian Empire. Achaemenid Period.

Chicago Style (17th ed.) Citation

Olmstead, A. T. A History of the Persian Empire. Achaemenid Period. Chicago, 1948.

MLA (8th ed.) Citation

Olmstead, A. T. A History of the Persian Empire. Achaemenid Period. 1948.

Warning: These citations may not always be 100% accurate.