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)
Conference in the Matter of Pollution of Lake Superior and its Tributary Basin in the States of Minnesota, Wisconsin, and Michigan (1971 : Duluth, Minn.)