3Irvine S,Cawood E, Richardson D, et al. Evidence of deteriorating semen quality in the United Kingdom: Birth cohort study in 577 men in Scotland over 11 years. BMJ, 1996,312:467.
4FIVNAT. Pregnancies and births resulting from in vitro fertilization:French national IVF registry,analysis of data 1986 to 1990.Fertil Steril, 1995,64 : 746.
5Auger J,Kunstmann JM,Czyglik F, et al. Decline in semen quality among fertile men in Parks during the past 20 years. N Engl J Med, 1995,332 : 281.
6Wu JQ, Yang QY, Tao JG, et al. Reference value of semen quality in Chinese young men. Contraception, 2002,65 : 365.
7Vierula M, Niemi M, Keiski A, et al. High and unchanged sperm counts of Finnish men, Int J Androl, 1996,19 : 11.
8Auger J, Jouannet P, Evidence for regional dofferences of semen quality among fertile French men:Federation Francaise des Centres d'Etude et de Conservation des Oeufs et du Sperme humains. Hum Reprod, 1997,12 : 740.
9Jensen TK,Andersson A,Hjollund Nil, et al. Inhibin B as a serum marker of spermatogenesis: Correlation to differences in sperm concentration and follicle-stimulating hormone levels. A study of 349 Donish men, J Clinic Endocrinol Metabol , 1997,82:4059.
10Fisch H, Feldshuh J, Goluboff ET, et al. Semen analyses in 1283 men from the United States over a 25 -year period: no decline in quality. Fertil Steril, 1996,65 : 1009.
