Okeke LI, George AO, Ogunbiyi AO, Wachtel M (2012-11). “Prevalence of Linea nigra in patients with benign prostatic hyperplasia and prostate carcinoma”. International journal of dermatology51 Suppl 1: 41–43. doi:10.1111/j.1365-4632.2012.05564.x. PMID23210957.
Okeke LI, George AO, Ogunbiyi AO, Wachtel M (2012-11). “Prevalence of Linea nigra in patients with benign prostatic hyperplasia and prostate carcinoma”. International journal of dermatology51 Suppl 1: 41–43. doi:10.1111/j.1365-4632.2012.05564.x. PMID23210957.