Não informado. (1940). Engineers digest: Review of engineering progress. Engineer's Digest Publications.
Lua i Stíl Chicago (17ú heag.)Não informado. Engineers Digest: Review of Engineering Progress. London: Engineer's Digest Publications, 1940.
Lua MLA (8ú heag.)Não informado. Engineers Digest: Review of Engineering Progress. Engineer's Digest Publications, 1940.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.