References
- J. Math. Anal. Appl. v.184 A generalization of the Hyers-Ulam-Rassias stability of approximate additive mappings Gavruta, P.
- Proc. Nat. Acad. Sci. On the stability of the linear functional equation Hyers, D.H.
- Proc. Amer. Math. Soc. v.72 On the stability of the linear functional equation Rassias, Th. M.
- J. Nat. Geometry v.1 What is left of Hyers-Ulam stability? Rassias, Th. M.;Tabor, J.
- Problems in Modern Mathematics, Chap. VI, Science editions Ulam, S.M.