Umadhay, G. (1953). Theory and practice of plane-table surveying.
Lua i Stíl Chicago (17ú heag.)Umadhay, Gregorio. Theory and Practice of Plane-table Surveying. 1953.
Lua MLA (9ú heag.)Umadhay, Gregorio. Theory and Practice of Plane-table Surveying. 1953.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.