@article{GDZPPN002385651, title = {A theorem on surfaces with a closed boundary.}, journal = {Mathematische Zeitschrift}, volume = {64}, year = {1956}, pages = {41-46}, zbl = {0070.16801}, url = {http://dml.mathdoc.fr/item/GDZPPN002385651} }
Hsiung, Chuan-Chih. A theorem on surfaces with a closed boundary.. Mathematische Zeitschrift, Tome 64 (1956) pp. 41-46. http://gdmltest.u-ga.fr/item/GDZPPN002385651/