Shofner, Frederick M. Explicit calibration of the pills II system / by Frederick M. Shofner - Washington, D.C. : U.S. Environmental Protection Agency, 1973 - v, 28 p. : ill. ; 28 cm. - Environmental Protection Technology Series . September 1973 EPA-600/2-73-011 Subjects--Topical Terms: Environmental protectionEnvironmentalism Dewey Class. No.: 363.7