Voir la notice de l'article provenant de la source European Digital Mathematics Library
@article{AM2_1978__17_136724, author = {Marvin Marcus}, title = {Pencils of real symmetric matrices and the numerical range.}, journal = {Aequationes mathematicae}, pages = {91--103}, publisher = {mathdoc}, volume = {17}, year = {1978}, zbl = {0386.15010}, url = {http://geodesic.mathdoc.fr/item/AM2_1978__17_136724/} }
Marvin Marcus. Pencils of real symmetric matrices and the numerical range.. Aequationes mathematicae, Tome 17 (1978), pp. 91-103. http://geodesic.mathdoc.fr/item/AM2_1978__17_136724/