@article{GDZPPN002432145, title = {On the Fundamental Group of a Visibility Manifold.}, journal = {Mathematische Zeitschrift}, volume = {192}, year = {1986}, pages = {347-352}, zbl = {0596.53035}, url = {http://dml.mathdoc.fr/item/GDZPPN002432145} }
Schroeder, V. On the Fundamental Group of a Visibility Manifold.. Mathematische Zeitschrift, Tome 192 (1986) pp. 347-352. http://gdmltest.u-ga.fr/item/GDZPPN002432145/