@article{10_4064_cm_24_2_259_269, author = {N. K. Kundu}, title = {On uniform symmetric derivatives}, journal = {Colloquium Mathematicum}, pages = {259--269}, publisher = {mathdoc}, volume = {24}, number = {2}, year = {1971}, doi = {10.4064/cm-24-2-259-269}, language = {en}, url = {http://geodesic.mathdoc.fr/articles/10.4064/cm-24-2-259-269/} }