@article{GDZPPN002482290, title = {Surfaces with Parallel Normalized Mean Curvature Vector.}, journal = {Monatshefte f\"ur Mathematik}, volume = {90}, year = {1980}, pages = {185-194}, zbl = {0435.53040}, url = {http://dml.mathdoc.fr/item/GDZPPN002482290} }
Chen, Bang-Yen. Surfaces with Parallel Normalized Mean Curvature Vector.. Monatshefte für Mathematik, Tome 90 (1980) pp. 185-194. http://gdmltest.u-ga.fr/item/GDZPPN002482290/