[1]
B. P. Sobreiro, A. M. Lucon, F. F. Pasqualotto, J. Hallak, K. S. Athayde, and S. Arap, “Semen analysis in fertile patients undergoing vasectomy: reference values and variations according to age, length of sexual abstinence, seasonality, smoking habits and caffeine intake”, Sao Paulo Med J, vol. 123, no. 4, pp. 161–166, Jul. 2005.