Gaya APA

JR, H, T. (1952). Mining practice at the Umbilin Coal Mine West-Central Sumatra (Memorandum) May 1952. . Bandung: Direktorat Batubara.

Gaya MLA

JR, HENRY, TARRING,. "Mining practice at the Umbilin Coal Mine West-Central Sumatra (Memorandum) May 1952.". Bandung: Direktorat Batubara, 1952. Batubara.