Riggs, H. (1969). Techniques of water- resources investigations of the united states geological survey: Frequency curves (2.bs.). Washington: United States Government Printing Office.
Chicago Style CitationRiggs, H.C. Techniques of Water- Resources Investigations of the United States Geological Survey: Frequency Curves. 2.bs. Washington: United States Government Printing Office, 1969.
MLA CitationRiggs, H.C. Techniques of Water- Resources Investigations of the United States Geological Survey: Frequency Curves. 2.bs. Washington: United States Government Printing Office, 1969.
Warning: These citations may not always be 100% accurate.