Não informado. (1981). Energy progress. American Institute of Chemical Engineers.
Lua i Stíl Chicago (17ú heag.)Não informado. Energy Progress. New York: American Institute of Chemical Engineers, 1981.
Lua MLA (8ú heag.)Não informado. Energy Progress. American Institute of Chemical Engineers, 1981.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.