@article{MAT_1968_12_1_a4,
     author = {R. T. Seeley},
     title = {The powers $A^s$ of an elliptic operator~$A$},
     journal = {Matematika},
     pages = {96--112},
     publisher = {mathdoc},
     volume = {12},
     number = {1},
     year = {1968},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MAT_1968_12_1_a4/}
}