Não informado. (1938). Occupational Hazards. Penton Publishing.
Lua i Stíl Chicago (17ú heag.)Não informado. Occupational Hazards. Cleveland, Ohio: Penton Publishing, 1938.
Lua MLA (8ú heag.)Não informado. Occupational Hazards. Penton Publishing, 1938.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.