@article{oai:tsukuba.repo.nii.ac.jp:00017200,
 author = {Koike, Naoyuki},
 issue = {3},
 journal = {Tsukuba Journal of Mathematics},
 month = {Dec},
 pages = {811--824},
 title = {Generalized helical immersions of a Riemannian manifold all of whose geodesics are closed into a Euclidean space},
 volume = {22},
 year = {1998}
}