Chellis, R. D. (1961). Pile Foundations. McGraw-Hill.
Lua i Stíl Chicago (17ú heag.)Chellis, Robert D. Pile Foundations. McGraw-Hill, 1961.
Lua MLA (8ú heag.)Chellis, Robert D. Pile Foundations. McGraw-Hill, 1961.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.