@article{oai:niigata-u.repo.nii.ac.jp:00002094,
 author = {Innami, Nobuhiro},
 issue = {1},
 journal = {Journal of the Mathematical Society of Japan, Journal of the Mathematical Society of Japan},
 month = {},
 pages = {89--103},
 title = {The class of second order equations which Riemannian geometry can be applied to},
 volume = {45},
 year = {1993}
}