@article{MZ_1987__194_173843,
     author = {Toshihiko Nishishiraho},
     title = {The {Convergence} and {Saturation} of {Iterations} of {Positive} {Linear} {Operators.}},
     journal = {Mathematische Zeitschrift},
     pages = {397--404},
     year = {1987},
     volume = {194},
     zbl = {0596.41036},
     url = {http://geodesic.mathdoc.fr/item/MZ_1987__194_173843/}
}