Walker, F. (1953). Geography from the air. MEthuen.
Lua i Stíl Chicago (17ú heag.)Walker, Frank. Geography from the Air. London: MEthuen, 1953.
Lua MLA (9ú heag.)Walker, Frank. Geography from the Air. MEthuen, 1953.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.