Spuler, B. (1977). Rulers and governments of the world. Bowker.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रSpuler, Bertold. Rulers and Governments of the World. Bowker, 1977.
एमएलए (9वां संस्करण) प्रशस्ति पत्रSpuler, Bertold. Rulers and Governments of the World. Bowker, 1977.
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