English: Y.OGURA:-On the structure and affinities of some fossil tree-ferns from Japan,Jour.Fac.Sci.Imp.Univ.Tokyo,Bot.Vol.I.p.368,t.8,1927;-On the structure and affinities of some cretaceous Prants from Hokkaido,I,II.ibid.Vol.II,part 5 ,part.7, .
Japanese: 小倉謙氏:-北海道白亜紀セノン世前期の植物化石研究