Sheldon, E. G. (1942). Sheldon's map reading and field sketching: Self instructor. Mingay.
Citación estilo ChicagoSheldon, Eric George. Sheldon's Map Reading and Field Sketching: Self Instructor. Sydney: Mingay, 1942.
Cita MLASheldon, Eric George. Sheldon's Map Reading and Field Sketching: Self Instructor. Mingay, 1942.
Warning: These citations may not always be 100% accurate.