@article{GDZPPN00226949X,
title = {A property of Haar's system of orthogonal functions.},
journal = {Mathematische Annalen},
volume = {90},
year = {1923},
pages = {38-45},
zbl = {49.0293.02},
url = {http://dml.mathdoc.fr/item/GDZPPN00226949X}
}
Walsh, J.L. A property of Haar's system of orthogonal functions.. Mathematische Annalen, Tome 90 (1923) pp. 38-45. http://gdmltest.u-ga.fr/item/GDZPPN00226949X/