Barlow, G. (1921). Earthwork (9th ed.). Superintendent, Government Press.
Lua i Stíl Chicago (17ú heag.)Barlow, G.T. Earthwork. 9th ed. Allahabad: Superintendent, Government Press, 1921.
Lua MLA (9ú heag.)Barlow, G.T. Earthwork. 9th ed. Superintendent, Government Press, 1921.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.