Origin, evolution and circulation of foreign coins in the Indian Ocean : proceedings of the Numismatic Workshop "Origin and Evolution of Coins" and the International Seminar "Circulation of foreign coins in Sri Lanka and ancient sea routes in the Indian Ocean", Colombo 8-10 September, 1994 - Bopearachchi, Osmund; Weerakkody, Don Patrick Mervyn (Manohar Publishers, 1998)