Hasumi, M. 1990. Seasonal dynamics of reproductive organs in male salamanders of the species Hynobius nigrescens. Copeia 1990: 367-377.
Komatsu, T. 1998. Immunohistochemical demonstration of cytoskeletal proteins in the testis of the Japanese Black Bear, Ursus thibetanus japonicus. Anatomia, Histologia, Embryologia 27: 209-213.
Krutzsch, P, H. 1982. Studies on prolonged spermatozoa survival in chiroptera: a morphological examination of storage and clearance of intrauterine and cauda epididymal spermatozoa in the bats Myotis lucifugus and M. velifer. American Journal of Anatomy 165: 421-434.