Conference proceedings : pollution of Lake Erie and its tributaries, fourth session : Cleveland, Ohio, October 4, 1968.

[Washington, D.C.] : [U.S. Dept. of the Interior, Federal Water Pollution Control Administration], 1968

Proceedings. Progress evaluation meeting: pollution of Lake Erie and its tributaries: Indiana, Michigan, New York, Ohio, Pennsylvania : June 4, 1968, Cleveland, Ohio.

[Washington, D.C.] : U.S. Federal Water Pollution Control Administration, 1969

Conference proceedings : pollution of Lake Erie and its tributaries, fourth session : Cleveland, Ohio, October 4, 1968.

Washington, D.C. : United States Government Printing Office, 1968