Gaya APA
Bronto, S. (1992).
Volcanoes and Their Volcanic Hazard Map Preparations (June 1992).
Yogyakarta:
Merapi Volcano Observatory.
Gaya MLA
Bronto, Sutikno.
"Volcanoes and Their Volcanic Hazard Map Preparations".
June 1992
Yogyakarta:
Merapi Volcano Observatory,
1992.
Text.