1. On the Hyers–Ulam stability of the generalized orthogonality equation in real Hilbert spaces;Chmieliński,1994
2. On the stability of the generalized orthogonality equation;Chmieliński,1994
3. On the superstability of the generalized orthogonality equation in Euclidean spaces;Chmieliński;Ann. Math. Sil.,1994
4. The stability of the Wigner equation in complex Hilbert spaces;Chmieliński;Wyż. Szkoła Ped. Kraków Rocznik Nauk.-Dydakt. Prace Matematyczne,1998
5. J. Chmieliński, Stability of angle-preserving mappings on the plane, Math. Inequal. Appl., in press