Elementary map and aerial photograph reading - USA Voorschrift, Basic Field Manual, 21-25 Mutual inspection for peace Aerial photography - USA Voorschrift, Technical Manual, 1-220 Elementry map and aerial photography reading - USA Voorschrift, Field Manual Advanced map and aerial photograph reading - USA Voorschrift, Field Manual, 21-26 Advanced map and aerial photograph reading - USA Basic Field Manual, FM 21-26