See E. E. Herzfeld, Archaeological History of Persia (1935); G. G. Cameron, History of Early Iran (1936, repr. 1969); P. S. R. Payne, The Splendor of Persia (1957); A. T. Olmstead, History of the Persian Empire (2d ed. 1969); R. Girshman et al., Persia, the Immortal Kingdom (1971); and M. W. Shuster, The Strangling of Persia (1912, repr. 1987).