1. Semen analysis: evidence for changing parameters of male fertility potential;Nelson, C.M.K.; Bunge, R.G.;Fertil Steril,1974
2. Secular trend in reported sperm counts;James, W.H.;Andrologia,1980
3. Changing parameters of donor semen;Leto, S.; Frensilli, F.J.,1981
4. Has the fertility of Danish men declined through the years in terms of semen quality? A comparison of semen qualities between 1952 and 1972;Bostofte, E.; Serup, J.; Rebbe, H.;Intj Fertil,1983
5. Depressed semen quality: a study over two decades;Osser, S.; Liedholm, P.; Ranstam, J.;Arch Androl,1984