John Charles Cheek, Tony Lesce (1988). Plainclothes and Off-duty Officer Survival. ISBN0398055289. p. 39. "Bunching up nullifies any chance of catching an adversary in a cross-fire. Figure 13. Crossfire is a very powerful tactic. It enables a pair of combatants to catch an opponent from two directions at once. Cross-fire can even menace an adversary."
