1. ACHD BAPC: 1971, Allegheny County Health Department Bureau of Air Pollution Control Air Pollution Index, 22 November, Robert Broughton Papers, Archives of Industrial and Environmental Society, AIS 77:42, University of Pittsburgh, Pittsburgh, Pennsylvania.
2. Air Quality Act of 1967, U.S. Statutes at Large 81:485, Section 105(a)(3).
3. Andrews, R. N. L.: 1999, Managing the Environment, Managing Ourselves: A History of American Environmental Policy, Yale University Press, New Haven, Connecticut.
4. Antommaria, P., Corn, M. and DeMaio, L.: 1965,‘Airborne particulates in Pittsburgh’, Science 150, 1476–1477.
5. Archives of Industrial and Environmental Society. Papers of the Allegheny County Air Pollution Control Advisory Committee, AIS 92:3, University of Pittsburgh Archives, Pittsburgh, Pennsylvania.