@article{1102945418, author = {Amelin, Charles F.}, title = {A numerical range for two linear operators.}, journal = {Pacific J. Math.}, volume = {49}, number = {2}, year = {1973}, pages = { 335-345}, language = {en}, url = {http://dml.mathdoc.fr/item/1102945418} }
Amelin, Charles F. A numerical range for two linear operators.. Pacific J. Math., Tome 49 (1973) no. 2, pp. 335-345. http://gdmltest.u-ga.fr/item/1102945418/