1. Projective planes in 3-manifolds;Epstein;Proc. London Math. Soc. (3),1961
2. L. Funar, Simple homotopy type and open 3-manifolds, Revue Roumaine Math. Pures Appl. (to appear);
3. Preprint available at http://www-fourier.ujf-grenoble.fr/~funar/thick1.ps.gz
4. Combinatorial Group Theory;Magnus,1966
5. A note on some contractible 4-manifolds;Mazur;Ann. of Math.,1961