@book{ 0-1377548767, title = {Grade and tonnage relationships among copper deposits: an analysis of the relationships between grades and tonnages of three types of copper deposits - porphyry, massive sulfide, and strata-bound}, series = {Geology and Resources of Copper Deposits}, author = {Singer, D. A. and Cox, Dennis P. and Drew, Lawrence J. and Chaffee, Maurice}, address = {Washington}, publisher = {United States Government Printing Office}, year = {1975}, language = {English}, url = {https://katalog.ub.tu-freiberg.de/Record/0-1377548767} }