| Karacan, Behavior Research Methods and Instrum., vol. 1, pp. 251-252, 1969. |
| Karacan, Archives Gen. Psychiatry, vol. 26, 1972, pp. 351-356. |
| Karacan, American J. of Psychiatry, vol. 132, Sep. 1975, pp. 932-937. |
| Barry et al., Urology, vol. 15, 1980, pp. 171-172. |
| Williams et al., Sleep Disorders: Diagnosis and Treatment, Chapt. 14, p. 353, 1978. |
| Metz et al., Urology, vol. XVIII, No. 3, Sep. 1981, pp. 268-270. |
| Allen, J. of Urology, vol. 126, Sep. 1981. |
| Wein et al., J. of Urology, vol. 126, Sep. 1981. |
| Karacan et al., Sexuality and Disability, vol. 1, No. 4, Winter 1978. |
| Wabrek, Sexology, 1982, pp. 199-203. |
| "Original Erectionmeter", Walter Koss OHG (Germany). |
| "Normative Studies on a New Device for Evaluation of Nocturnal Penile Tumescence", American Urological Association, Inc., by Alvaro Morales, Peter G. Marshall, David H. Surridge & Janet Fenemore, Presented at 77th Annual Meeting (May 1982), by Dr. Morales. |
| Article: "Methodology: The Measurement of Human Penile Tumescence", Rosen and Keefe, Psychophysiology, vol. 15, No. 4. |