@article{02107564,
title = {The Ulam stability problem in approximation of approximately quadratic mappings by quadratic mappings.},
journal = {JIPAM. Journal of Inequalities in Pure \& Applied Mathematics [electronic only]},
volume = {5},
year = {2004},
zbl = {1055.39041},
language = {en},
url = {http://dml.mathdoc.fr/item/02107564}
}
Rassias, John Michael. The Ulam stability problem in approximation of approximately quadratic mappings by quadratic mappings.. JIPAM. Journal of Inequalities in Pure & Applied Mathematics [electronic only], Tome 5 (2004) . http://gdmltest.u-ga.fr/item/02107564/