Enger, E., & Smith, B. (1995). Pollution and policy. McGraw-Hill.
Lua i Stíl Chicago (17ú heag.)Enger, Eldon, agus Bradley Smith. Pollution and Policy. Boston: McGraw-Hill, 1995.
Lua MLA (9ú heag.)Enger, Eldon, agus Bradley Smith. Pollution and Policy. McGraw-Hill, 1995.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.