@article{CMH_1985__60_140005,
     author = {J.-C. Hausmann and Shmuel Weinberger},
     title = {Caract\'eristiques d'euler et groupes fondamentaux des vari\'et\'es de dimension 4.},
     journal = {Commentarii mathematici Helvetici},
     pages = {139--144},
     publisher = {mathdoc},
     volume = {60},
     year = {1985},
     zbl = {0566.57011},
     url = {http://geodesic.mathdoc.fr/item/CMH_1985__60_140005/}
}