Não informado. (1971). Petroleum Refining and Petrochemicals Literature Abstracts. American Petroleum Institute.
Lua i Stíl Chicago (17ú heag.)Não informado. Petroleum Refining and Petrochemicals Literature Abstracts. New York: American Petroleum Institute, 1971.
Lua MLA (8ú heag.)Não informado. Petroleum Refining and Petrochemicals Literature Abstracts. American Petroleum Institute, 1971.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.