Author,Title,Journal,ISSN,Publisher,Date,Volume,Number,Page,URL,URL(DOI) MAKINO S.,A cytological study on the maturation and fertilization of the egg of Hynobius retardatus (an urodelan amphibian),J Fac Sci Hokkaido Imp Univ Ser IV Zool,,,1934,3,,117-167,https://cir.nii.ac.jp/crid/1574231874391663104,