1. [Gr] M. Gromov, Volume and bounded cohomology, Inst. Hautes Études Sci. Publ. Math. (1982), no. 56, 5–99 (1983).
2. [Po1] V. poénaru, Infinite processes and the $3$-dimensional Poincaré Conjecture I: the collapsible pseudo-spine representation theorem, to appear in Topology.
3. [Po2] V. Poénaru, Almost convex groups, Lipschitz combing, and $\pi^ \infty_1$ for universal covering spaces of closed $3$-manifolds, Prépublication d'Orsay 90-09, 1990.
4. [Po3] V. Poénaru, Geometry “à la Gromov” for the fundamental group of a closed $3$-manifold $M^3$ and the simple connectivity at infinity of $M^3$, Prépublication d'Orsay 90-62, 1990.