@article{GDZPPN002408163,
title = {Smoothness Indices for Convex Functions and the Unique Hahn-Banach Extension Problem.},
journal = {Mathematische Zeitschrift},
volume = {121},
year = {1971},
pages = {95-110},
zbl = {0196.13605},
url = {http://dml.mathdoc.fr/item/GDZPPN002408163}
}
Holmes, Richard. Smoothness Indices for Convex Functions and the Unique Hahn-Banach Extension Problem.. Mathematische Zeitschrift, Tome 121 (1971) pp. 95-110. http://gdmltest.u-ga.fr/item/GDZPPN002408163/