@article{bwmeta1.element.bwnjournal-article-fmv42i2p339bwm,
author = {J. Lipi\'nski},
title = {Une propri\'et\'e des ensembles {f'(x)>a}},
journal = {Fundamenta Mathematicae},
volume = {41},
year = {1955},
pages = {339-342},
zbl = {0065.28803},
language = {fra},
url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-fmv42i2p339bwm}
}
Lipiński, J. Une propriété des ensembles {f'(x)>a}. Fundamenta Mathematicae, Tome 41 (1955) pp. 339-342. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-fmv42i2p339bwm/