• A. T. Olmstead, History of the Persian Empire, 1948.
• Pauly-Wissowa (comprehensive encyclopaedia on Antiquity; in German).
• Robert Dick Wilson. The Book of Daniel: A Discussion of the Historical Questions, 1917. Available on home.earthlink.net.
• Rüdiger Schmitt, "Der Titel 'Satrap'", in Studies Palmer ed. Meid (1976), 373–390.
• Rencana ini menggabungkan teks daripada Ensiklopedia Britannica Edisi Ke-11, sebuah terbitan yang kini di domain awam.

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• Cormac McCarthy, All the Pretty Horses, 1992.