Jelaskan Lihat pula dari Ngultrum Bhutan

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Rhodes, Nicholas:The Coinage of Bhutan. Oriental Numismatic Society, Information Sheet no 16, January 1977.

Rhodes, Nicholas: "Coinage in Bhutan".Journal of Bhutan Studies.. The Centre of Bhutan Studies, vol. 1, no. 1, Thimphu, Autumn, 1999, p. 84-113.

Rhodes, Nicholas: "The Monetisation of Bhutan". Journal of Bhutan Studies.. The Centre of Bhutan Studies, vol. 2, no. 1, Thimphu, Winter 2000, p. 85-103.