@article{10_4153_CJM_1976_007_7,
     author = {Ackerman, Neill H. and Hsiung, C. C.},
     title = {Isometry of {Riemannian} {Manifolds} to {Spheres,} {II}},
     journal = {Canadian journal of mathematics},
     pages = {63--72},
     year = {1976},
     volume = {28},
     number = {1},
     doi = {10.4153/CJM-1976-007-7},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1976-007-7/}
}