Norma relacionada
Practice Relating to Rule 107. Spies
Section A. Definition of spies
A publication on Philippine Military Law (1956) states:
A spy is a person who, without authority and secretly, or under a false pretext, contrives to enter within the lines of an army for the purpose of obtaining material information and communicating it to the enemy; or one who, being by authority within the lines, attempts secretly to accomplish such purpose. 
Claro C. Gloria, Philippine Military Law, Capitol Publishing House, Quezon City, 1956, p. 263.