@article{MZ_1996__221_1_174843,
     author = {M. Reimer},
     title = {A short proof of a result of {Kogbetliantz} on the positivity of certain {Ces\`aro} means.},
     journal = {Mathematische Zeitschrift},
     pages = {189--192},
     year = {1996},
     volume = {221},
     number = {1},
     zbl = {0840.41019},
     url = {http://geodesic.mathdoc.fr/item/MZ_1996__221_1_174843/}
}