@article{1183530641,
author = {Heil, Wolfgang},
title = {On $P^2$-irreducible 3-manifolds},
journal = {Bull. Amer. Math. Soc.},
volume = {75},
number = {5},
year = {1969},
pages = { 772-775},
language = {en},
url = {http://dml.mathdoc.fr/item/1183530641}
}
Heil, Wolfgang. On $P^2$-irreducible 3-manifolds. Bull. Amer. Math. Soc., Tome 75 (1969) no. 5, pp. 772-775. http://gdmltest.u-ga.fr/item/1183530641/