Legget, R. F. (1973). Cities and Geology. McGraw-Hill.
Dyfyniad Arddull ChicagoLegget, Robert F. Cities and Geology. New York: McGraw-Hill, 1973.
Dyfyniad MLALegget, Robert F. Cities and Geology. McGraw-Hill, 1973.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.