@article{GDZPPN002405547,
title = {Convexity Theorems for N\"orlund and Strong N\"orlund Summability.},
journal = {Mathematische Zeitschrift},
volume = {111},
year = {1969},
pages = {357-363},
zbl = {0182.08504},
url = {http://dml.mathdoc.fr/item/GDZPPN002405547}
}
Cass, Frank P. Convexity Theorems for Nörlund and Strong Nörlund Summability.. Mathematische Zeitschrift, Tome 111 (1969) pp. 357-363. http://gdmltest.u-ga.fr/item/GDZPPN002405547/