1. D. E. Blair -G. D. Ludden -K. Yano,Semi-invariant immersion, Ködai Math. Sem. Rep.,27 (1976), pp. 313–319.
2. J. Erbacher,Reduction of the codimension of an isometric immersion, J. Diff. Geo.,5 (1971), pp. 333–340.
3. S.-S. Eum -U.-H. Ki -U. K. Kim -Y. H. Kim,Submanifolds of codimension 3 of a Kaehlerian manifold (I), J. Korean Math. Soc.,16 (1980), pp. 137–153.
4. S.-S. Eum -U.-H. Ki -U. K. Kim -Y. H. Kim,Submanifolds of codimension 3 of a Kaehlerian manifold (II), J. Korean Math. Soc.,17 (1981), pp. 211–228.
5. B. Y. Chen -K. Yano,Pseudo-umbilical submanifolds in a Riemannian manifold of constant curvature, Diff. Geo. in honor of K.Yano, Kinokuniya Tokyo, (1972), pp. 61–71.