On Cauchy-type functional equations. - Elqorachi Elhoucien; Mohamed Akkouchi (Int. J. Math. Math. Sci., 2004)

The superstability of d'Alembert's functional equation on the Heisenberg group. - Belaid Bouikhalene; Elqorachi Elhoucien; John Michael Rassias (Appl. Math. Lett., 2010)