Ettlich, W. F., Hinrichs, D. J., & Lineck, T. S. (1978). Operations manual: Sludge handling and conditioning. Washington, D.C: Government Printing Office : United States. Environmental Protection Agency. Office of Water Program Operations.
Παραπομπή Chicago StyleEttlich, William F., Daniel J. Hinrichs, and Thomas S. Lineck. Operations Manual: Sludge Handling and Conditioning. Washington, D.C: Government Printing Office : United States. Environmental Protection Agency. Office of Water Program Operations, 1978.
Παραπομπή MLAEttlich, William F., Daniel J. Hinrichs, and Thomas S. Lineck. Operations Manual: Sludge Handling and Conditioning. Washington, D.C: Government Printing Office : United States. Environmental Protection Agency. Office of Water Program Operations, 1978.