@article{MZ_1982__179_173145,
     author = {Ky Fan},
     title = {Iteration of {Analytic} {Functions} of {Operators.}},
     journal = {Mathematische Zeitschrift},
     pages = {293--298},
     year = {1982},
     volume = {179},
     zbl = {0465.47017},
     url = {http://geodesic.mathdoc.fr/item/MZ_1982__179_173145/}
}