@article{1029000103,
author = {Ku, Hsu-tung and Ku, Mei-chin},
title = {Semifree differentiable actions of $S^1$ on homotopy $(4k+3)$-spheres.},
journal = {Michigan Math. J.},
volume = {15},
number = {1},
year = {1968},
pages = { 471-476},
language = {en},
url = {http://dml.mathdoc.fr/item/1029000103}
}
Ku, Hsu-tung; Ku, Mei-chin. Semifree differentiable actions of $S^1$ on homotopy $(4k+3)$-spheres.. Michigan Math. J., Tome 15 (1968) no. 1, pp. 471-476. http://gdmltest.u-ga.fr/item/1029000103/