Proceedings of the Romanian Academy. Series A. Mathematics, Physics, Technical Sciences, Information Science (Proc. Rom. Acad. Ser. A Math. Phys. Tech. Sci. Inf. Sci.) (20130101), 14, no.~3, 193-197. ISSN: 1454-9069 (print).
Revue Roumaine de Mathématiques Pures et Appliquées. Romanian Journal of Pure and Applied Mathematics (Rev. Roumaine Math. Pures Appl.) (20110101), 56, no.~4, 303-315. ISSN: 0035-3965 (print).
Proceedings of the Romanian Academy. Series A. Mathematics, Physics, Technical Sciences, Information Science (Proc. Rom. Acad. Ser. A Math. Phys. Tech. Sci. Inf. Sci.) (20110101), 12, no.~3, 197-202. ISSN: 1454-9069 (print).