Philippines (Commonwealth) Bureau of Mines & Philippines (Republic). Bureau of Mines. Information circular. no. 1-. [s.n.
Čikaški stil citiranja (17. izdanje)Philippines (Commonwealth) Bureau of Mines i Philippines (Republic). Bureau of Mines. Information Circular. No. 1-. Manila: [s.n.
MLA način citiranja (9. izdanje)Philippines (Commonwealth) Bureau of Mines i Philippines (Republic). Bureau of Mines. Information Circular. No. 1-. [s.n.
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