@article{oai:ynu.repo.nii.ac.jp:00006854,
 author = {Yasukura, Osami},
 issue = {2},
 journal = {Yokohama Mathematical Journal = 横濱市立大學紀要. D部門, 数学},
 month = {},
 note = {application/pdf, A quaternionic version of Schur's theorem on space forms is proved as a corollary of the construction of semi-symplectic triple system on each tangent space, which is well-defined because the Riemannian curvature tensor is invariant by the action of ＄Sp(1)＄ .},
 pages = {121--142},
 title = {SYMPLECTIC TRIPLE SYSTEMS AND QUATERNION-KAHLER MANIFOLDS : Dedicated to Professor Hisao Nakagawa on his sixtieth birthday},
 volume = {40},
 year = {1993}
}