Gaya APA
Hadikusumo, . (1975).
Volcanic Activities in Indonesia during 1971 (Mei 1975).
Yogyakarta:
Direktorat Vulkanologi.
Gaya MLA
Hadikusumo, .
"Volcanic Activities in Indonesia during 1971".
Mei 1975
Yogyakarta:
Direktorat Vulkanologi,
1975.
Text.