@article{GDZPPN002432900, title = {Sharpened Forms of an Inequality of Von Neumann.}, journal = {Mathematische Zeitschrift}, volume = {194}, year = {1987}, pages = {7-14}, zbl = {0631.47004}, url = {http://dml.mathdoc.fr/item/GDZPPN002432900} }
Fan, Ky. Sharpened Forms of an Inequality of Von Neumann.. Mathematische Zeitschrift, Tome 194 (1987) pp. 7-14. http://gdmltest.u-ga.fr/item/GDZPPN002432900/