@article{10_4153_CJM_2009_034_4,
     author = {Maeda, Sadahiro and Udagawa, Seiichi},
     title = {Characterization of {Parallel} {Isometric} {Immersions} of {Space} {Forms} into {Space} {Forms} in the {Class} of {Isotropic} {Immersions}},
     journal = {Canadian journal of mathematics},
     pages = {641--655},
     year = {2009},
     volume = {61},
     number = {3},
     doi = {10.4153/CJM-2009-034-4},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-2009-034-4/}
}