@article{1102948656, author = {Heil, Wolfgang}, title = {Testing $3$-manifolds for projective planes.}, journal = {Pacific J. Math.}, volume = {49}, number = {2}, year = {1973}, pages = { 139-145}, language = {en}, url = {http://dml.mathdoc.fr/item/1102948656} }
Heil, Wolfgang. Testing $3$-manifolds for projective planes.. Pacific J. Math., Tome 49 (1973) no. 2, pp. 139-145. http://gdmltest.u-ga.fr/item/1102948656/