@article{10_4064_sm_41_2_191_206,
     author = {Michael Fisher},
     title = {Fractional powers of operators and {Bessel} potentials on {Hilbert} space},
     journal = {Studia Mathematica},
     pages = {191--206},
     publisher = {mathdoc},
     volume = {41},
     number = {2},
     year = {1972},
     doi = {10.4064/sm-41-2-191-206},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/sm-41-2-191-206/}
}