1) Palermo G, et al : Pregnancies after intracytoplasmic injection of single spermatozoa into an oocyte. Lancet 340 : 17─18, 1992
2) World Health Organization, Department of Reproductive Health and Research : WHO laboratory manual for the examination and processing of human semen. 5th ed. 2010
3) Takihara H, et al : Significance of testicular size measurement in andrology. I. A new orchiometer and its clinical application. Fertil Steril 39 : 836─840, 1983
4) Hendry WF, et al : 200 infertile males : correlation of chromosome, histological, endocrine and clinical studies. Br J Urol 47 : 899─908, 1975
5) Bourrouillou G, et al : Role and contribution of karyotyping in male infertility. Prog Urol 2 : 189─195, 1992
6) Matsuda T, et al : Chromosomal survey of 1001 subfertile males : incidence and clinical features of males with chromosomal anomalies. Hinyokika Kiyo 38 : 803─809, 1992
7) Vogt PH, et al : Human Y chromosome azoospermia factors(AZF)mapped to different subregions in Yq11. Hum Mol Genet 5 : 933─943, 1996
8) Johnsen SG : Testicular biopsy score count- a method for registration of spermatogenesis in human testes : normal values and results in 335 hypogonadal males. Hormones 1 : 2─25, 1970
9) Schlegel PN : Testicular sperm extraction : microdissection improves sperm yield with minimal tissue extraction. Hum Reprod 14 : 131─135, 1999
10) Okada H, et al : Conventional versus microdissection testicular sperm extraction for nonobstructive azoospermia. J Urol 68 : 1063─1067, 2002
11) Sato T, et al : In vitro production of functional sperm in cultured neonatal mouse testes. Nature 471 : 504─507, 2011
12) Finkel DM, et al : Stimulation of spermatogenesis by gonadotropins in men with hypogonadotropic hypogonadism. N Engl J Med 313 : 651─655, 1985