@article{GDZPPN002414244,
title = {Universal Covering Maps for Variable Regions.},
journal = {Mathematische Zeitschrift},
volume = {136},
year = {1974},
pages = {7-20},
zbl = {0316.30009},
url = {http://dml.mathdoc.fr/item/GDZPPN002414244}
}
Hejhal, Dennis A. Universal Covering Maps for Variable Regions.. Mathematische Zeitschrift, Tome 136 (1974) pp. 7-20. http://gdmltest.u-ga.fr/item/GDZPPN002414244/