@article{GDZPPN002402599, title = {On the Hammard Product.}, journal = {Mathematische Zeitschrift}, volume = {105}, year = {1968}, pages = {365-366}, zbl = {0162.04204}, url = {http://dml.mathdoc.fr/item/GDZPPN002402599} }
Ballantine, Charles S. On the Hammard Product.. Mathematische Zeitschrift, Tome 105 (1968) pp. 365-366. http://gdmltest.u-ga.fr/item/GDZPPN002402599/