1. “Clean Air Amendments of 1970,” 42 U.S.C. 7401, 81 Stat. 485.
2. “Clean Air Act Amendments of 1977,” Public Law 95-95 (Aug. 7, 1977).
3. “Clean Air Act Amendments of 1990,” Public Law 101-549, 104 Stat. 2399 (Nov. 15, 1990).
4. “Enabling Document for Regulations Governing Compliance Extensions for Early Reductions of Hazardous Air Pollutants,” EPA-450/3-91-013, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, Draft (July 1991).