International Mathematical Forum. Journal for Theory and Applications (Int. Math. Forum) (20130101), 8, no.~33-36, 1709-1717. ISSN: 1312-7594 (print).eISSN: 1314-7536.
International Mathematical Forum. Journal for Theory and Applications (Int. Math. Forum) (20100101), 5, no.~5-8, 251-258. ISSN: 1312-7594 (print).eISSN: 1314-7536.