@article{SF_1986__33_134809,
     author = {R. de Laubenfels},
     title = {Scalar-type spectral operators and holomorphie semigroups.},
     journal = {Semigroup forum},
     pages = {257--264},
     publisher = {mathdoc},
     volume = {33},
     year = {1986},
     zbl = {0583.47040},
     url = {http://geodesic.mathdoc.fr/item/SF_1986__33_134809/}
}