@article{CMUC_1994__35_1_a2,
     author = {Appell, J\"urgen and Sim\~oes, Marilda A. and Zabrejko, Petr P.},
     title = {On the $\Cal L$-characteristic of fractional powers of linear operators},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {21--34},
     publisher = {mathdoc},
     volume = {35},
     number = {1},
     year = {1994},
     mrnumber = {1292579},
     zbl = {0806.47014},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1994__35_1_a2/}
}