Conference in the Metter of Pollution of Lake Michigan and its Tributary Basin in the States of Wisconsin, Illinois, Indiana, and Michigan (3rd session reconvened in workshop sessions : 1970 : Chicago, Ill.)
Conference in the Matter of Pollution of Lake Michigan and its Tributary Basin in the States of Wisconsin, Illinois, Indiana, and Michigan (4th : Chicago, #d 1972.)
Conference in the Matter of Pollution of Lake Michigan and its Tributary Basin in the States of Wisconsin, Illinois, Indiana, and Michigan (4th : 1972 : Chicago)