O’Hara, B., Smith, S., Bird, G., Persico, A., Suarez, B., Cutting, G., & Uhl, G. (1969). Dopamine D2 receptor RFLPs, haplotypes and their association with substance use in black and Caucasian research volunteers. Human Heredity, 43(4), 209-18. https://doi.org/10.1159/000154133 (Original work published 1969)

Smith, S., O’Hara, B., Persico, A., Gorelick, D., Newlin, D., Vlahov, D., … Uhl, G. (1992). Genetic vulnerability to drug abuse. The D2 dopamine receptor Taq I B1 restriction fragment length polymorphism appears more frequently in polysubstance abusers. Archives of General Psychiatry, 49(9), 723-7. https://doi.org/10.1001/archpsyc.1992.01820090051009