Não informado. (1969). Industrial Lubrication and Tribology. Petersen Publishing.
Lua i Stíl Chicago (17ú heag.)Não informado. Industrial Lubrication and Tribology. Droitwich, Inglaterra: Petersen Publishing, 1969.
Lua MLA (8ú heag.)Não informado. Industrial Lubrication and Tribology. Petersen Publishing, 1969.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.