@article{GDZPPN002421690,
title = {A Hopf Inequality for Branch Sets.},
journal = {Mathematische Zeitschrift},
volume = {162},
year = {1978},
pages = {81-92},
zbl = {0373.55002},
url = {http://dml.mathdoc.fr/item/GDZPPN002421690}
}
DeGeorge, David L.; Reddy, William L. A Hopf Inequality for Branch Sets.. Mathematische Zeitschrift, Tome 162 (1978) pp. 81-92. http://gdmltest.u-ga.fr/item/GDZPPN002421690/