@article{MZ_1972__124_171671,
     author = {Dany Leviatan},
     title = {On {Gamma-Type} {Approximation} {Operators.}},
     journal = {Mathematische Zeitschrift},
     pages = {208--212},
     publisher = {mathdoc},
     volume = {124},
     year = {1972},
     zbl = {0214.31503},
     url = {http://geodesic.mathdoc.fr/item/MZ_1972__124_171671/}
}