Gaya APA

HAYS, W. (1981). Facing geologic and hydrologic hazards earth-science considerations: Geological survey professional paper 1240 B . : U.S. Government Printing Office.

Gaya MLA

HAYS, W.W.. "Facing geologic and hydrologic hazards earth-science considerations: Geological survey professional paper 1240 B". : U.S. Government Printing Office, 1981. Laporan.