(EN) Peter Lev, The Fifties: Transforming the Screen, 1950-1959, vol.7 di Transforming the Screen, 1950-1959, University of California Press, 2006, p. 177, ISBN 978-0-520-24966-0.
«Invasion films were common in the 1950s featuring a variety of aliens portrayed as superior to earthlings both in intelligence and technology . In these films, aliens represent what some Americans feared about the Soviets. Invaders, friends or enemies, and often with the help of robots, either come to warn earthlings or destroy them with superior technology. Sometimes the invaders use the strategy of infiltration, taking over the minds of the people, making slaves of them or appropriating their bodies, thus making war unnecessary.»
