Gaya APA

Johnston, D, A. (1983). David A. Johston Cascades Volcano Observatory Monthly Report December 1982 and January 1983 (Tahun 1983). Washington: U.S. Geological Survey.

Gaya MLA

Johnston, David, A.. "David A. Johston Cascades Volcano Observatory Monthly Report December 1982 and January 1983". Tahun 1983 Washington: U.S. Geological Survey, 1983. Text.