Wester, P. J. Mindanao and the Sulu Archipelago: Their natural resources and opportunities for development (2nd rev. ed.). Bureau of Printing.
শিকাগো স্টাইল (17 তম সংস্করণ) উদ্ধৃতিWester, Peter Johnson. Mindanao and the Sulu Archipelago: Their Natural Resources and Opportunities for Development. 2nd rev. ed. Manila: Bureau of Printing.
M.L.A (9 ম সংস্করণ) উদ্ধৃতিWester, Peter Johnson. Mindanao and the Sulu Archipelago: Their Natural Resources and Opportunities for Development. 2nd rev. ed. Bureau of Printing.
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