@article{1029003237, author = {James, David M.}, title = {Smooth $S^1$ actions on homotopy ${\bf C}{\rm P}^4$'s.}, journal = {Michigan Math. J.}, volume = {32}, number = {1}, year = {1985}, pages = { 259-266}, language = {en}, url = {http://dml.mathdoc.fr/item/1029003237} }
James, David M. Smooth $S^1$ actions on homotopy ${\bf C}{\rm P}^4$'s.. Michigan Math. J., Tome 32 (1985) no. 1, pp. 259-266. http://gdmltest.u-ga.fr/item/1029003237/