Gaya APA
Foxworthy, B, L. (1980).
Volcanic Eruption of 1980 at Mount St. Halens The First 100 Days .
Washington:
Geological Survey profesional paper.
Gaya MLA
Foxworthy, Bruce, L.
"Volcanic Eruption of 1980 at Mount St. Halens The First 100 Days".
Washington:
Geological Survey profesional paper,
1980.
Text.