	Authors	Year	Title
	Ehiro	1966	Latest Permian ammonoid Paratirolites from the Ofunato district, Southern Kitakami Massif, Northeast Japan. Transactions and Proceedings of the Palaeontological Society of Japan, n.ser., 184: 592-596, 3 figs.
	Ehiro	2002	A time gap at the Permian-Triassic boundary in the South Kitakami Belt, Northeast Japan: An examination based on ammonoid fossils. Saito-Ho-on Kai Museum Research Bulletin, 68: 1-12, 3 fig.