1. Zuckerman M . Physiological measures of sexual arousal in the human. Psychol Bull 1971; 75: 297–329.
2. Masters W, Johnson V . Human Sexual Response. Little Brown & Company: Boston, 1966.
3. Sokolov EN . Neuronal models and the orienting reflex. In: Brazier MAB (ed). The Central Nervous System and Behavior Josiah Macy Jr Foundation Publications: Madison, NJ, 1960 pp 187–276.
4. Brown CC . The techniques of plethysmography. In: Brown CC (ed). Methods in Psychophysiology. Williams & Wilkins Company: Baltimore, MA, 1967 pp 54–74.
5. Geer JH, Morokoff P, Greenwood P . Sexual arousal in women: the development of a measurement device for vaginal blood volume. Arch Sex Behav 1974; 3: 559–564.