1. 1) WILLIAMS TD. Humboldt penguin. The Penguins. Oxford Univ. Press. (1995)
2. 2) OHIRA M. Study of the practical technique on the deep freezing preservation of chicken semen. Bull Gifu Prefe Poult Expe Stati. (1994) vol.41, p.19-22.
3. 3) IRITANI A. Livestock. Spermatology. Univ. of Tokyo Press. (1992)
4. 4) GOTO K. The artificial reproduction technology of domestic animals. Iden. (1996) vol.50, p.18-23.
5. 5) MOHRI H. The conservation of spermatozoa and genetic resource. Spermatology. Univ. of Tokyo Press. (1992)