Não informado. (1969). Rock Mechanics and Rock Engineering. Springer Verlag.
Lua i Stíl Chicago (17ú heag.)Não informado. Rock Mechanics and Rock Engineering. Wien: Springer Verlag, 1969.
Lua MLA (8ú heag.)Não informado. Rock Mechanics and Rock Engineering. Springer Verlag, 1969.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.