@article{1029003752, author = {M\"uller, Vladim\'\i r}, title = {The numerical radius of a commuting product.}, journal = {Michigan Math. J.}, volume = {35}, number = {1}, year = {1988}, pages = { 255-260}, language = {en}, url = {http://dml.mathdoc.fr/item/1029003752} }
Müller, Vladimír. The numerical radius of a commuting product.. Michigan Math. J., Tome 35 (1988) no. 1, pp. 255-260. http://gdmltest.u-ga.fr/item/1029003752/