@article{1103039124,
author = {Schaefer, H. H.},
title = {On nonlinear positive operators.},
journal = {Pacific J. Math.},
volume = {9},
number = {4},
year = {1959},
pages = { 847-860},
language = {en},
url = {http://dml.mathdoc.fr/item/1103039124}
}
Schaefer, H. H. On nonlinear positive operators.. Pacific J. Math., Tome 9 (1959) no. 4, pp. 847-860. http://gdmltest.u-ga.fr/item/1103039124/