Gaya APA

Stephens, C, D. et al (1992). Precursory Swarms of Long-Period Events at Redoubt Volcano (1989-1990), ALASKA : Their Origin and Use as a Forecasting Tool (Tahun 1992). Bandung: U.S Geological Survey.

Gaya MLA

Stephens, Christopher, D.. et al. "Precursory Swarms of Long-Period Events at Redoubt Volcano (1989-1990), ALASKA : Their Origin and Use as a Forecasting Tool". Tahun 1992 Bandung: U.S Geological Survey, 1992. Text.