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@article{MAN_1989__284_4_164572, author = {Klaus-J. Engel}, title = {Polynomial operator matrices as semigroup generators: the 2 x 2 case.}, journal = {Mathematische Annalen}, pages = {563--576}, publisher = {mathdoc}, volume = {284}, number = {4}, year = {1989}, zbl = {0652.34013}, url = {http://geodesic.mathdoc.fr/item/MAN_1989__284_4_164572/} }
Klaus-J. Engel. Polynomial operator matrices as semigroup generators: the 2 x 2 case.. Mathematische Annalen, Tome 284 (1989) no. 4, pp. 563-576. http://geodesic.mathdoc.fr/item/MAN_1989__284_4_164572/