Lewis Vance Cummings, Alexander the Great (Grove Press, 2004) page 402.
E. H. Warmington, The Commerce Between the Roman Empire and India (Cambridge University Press Archive, 2014) page 24.
Guy Le Strange, The Lands of the Eastern Caliphate: Mesopotamia, Persia, and Central Asia from the Moslem Conquest to the Time of Timur (Cosimo, Inc., 2010)page 318.
E. Yarshater, The Cambridge History of Iran: Seleucid Parthian (Cambridge University Press, 1983) page 773.
G. Le Strange, The Lands of the Eastern Caliphate, Cambridge University Press 2011. page 317
