Campbell, Donald T. (January 1979). "Assessing the impact of planned social change". Evaluation and Program Planning. 2 (1): 67–90. doi:10.1016/0149-7189(79)90048-X.
Wike, Edward L. (1 September 2016). "Water Beds and Sexual Satisfaction: Wike's Law of Low Odd Primes (WLLOP)". Psychological Reports. 33 (1): 192–194. doi:10.2466/pr0.1973.33.1.192. S2CID145176823.
Wike, Edward L. (1 September 2016). "Water Beds and Sexual Satisfaction: Wike's Law of Low Odd Primes (WLLOP)". Psychological Reports. 33 (1): 192–194. doi:10.2466/pr0.1973.33.1.192. S2CID145176823.