@article{ASNSP_1993_4_20_3_387_0,
     author = {Po\'enaru, V. and Tanasi, C.},
     title = {Hausdorff combing of groups and $\pi ^\infty _1$ for universal covering spaces of closed 3-manifolds},
     journal = {Annali della Scuola Normale Superiore di Pisa - Classe di Scienze},
     pages = {387--414},
     publisher = {Scuola normale superiore},
     volume = {Ser. 4, 20},
     number = {3},
     year = {1993},
     zbl = {0821.57014},
     language = {en},
     url = {http://www.numdam.org/item/ASNSP_1993_4_20_3_387_0/}
}