Riegman PH, Vlietstra RJ, Klaassen P, van der Korput JA, Geurts van Kessel A, Romijn JC, Trapman J. The prostate-specific antigen gene and the human glandular kallikrein-1 gene are tandemly located on chromosome 19. FEBS Lett. 1989 Apr 10;247(1):123–6. doi: 10.1016/0014-5793(89)81253-0. PMID: 2468530.