Sheldon, E. G. (1942). Sheldon's map reading and field sketching: Self instructor. Mingay.
Citazione stile Chigago Style (17a edizione)Sheldon, Eric George. Sheldon's Map Reading and Field Sketching: Self Instructor. Sydney: Mingay, 1942.
Citatione MLA (8a ed.)Sheldon, Eric George. Sheldon's Map Reading and Field Sketching: Self Instructor. Mingay, 1942.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.