@article{MAN_1970__184_161921,
     author = {S.K. BERBERIAN},
     title = {Some {Conditions} on an {Operator} {Implying} {Normality.}},
     journal = {Mathematische Annalen},
     pages = {188--192},
     publisher = {mathdoc},
     volume = {184},
     year = {1970},
     zbl = {0176.11301},
     url = {http://geodesic.mathdoc.fr/item/MAN_1970__184_161921/}
}