@article{2274,
author = {Austin, D.G.},
title = {A Lipschitzian characterization of approximately differentiable functions},
journal = {Portugaliae mathematica},
volume = {15},
year = {1956},
pages = {19-29},
zbl = {0072.27904},
mrnumber = {0084024},
language = {en},
url = {http://dml.mathdoc.fr/item/2274}
}
Austin, D.G. A Lipschitzian characterization of approximately differentiable functions. Portugaliae mathematica, Tome 15 (1956) pp. 19-29. http://gdmltest.u-ga.fr/item/2274/