Bulletin of the Malaysian Mathematical Sciences Society (Bull. Malays. Math. Sci. Soc.) (20230101), 46, no.~6, Paper No 185, 15~pp. ISSN: 0126-6705 (print).eISSN: 2180-4206.
Bulletin of the Malaysian Mathematical Sciences Society (Bull. Malays. Math. Sci. Soc.) (20230101), 46, no.~4, Paper No 139, 16~pp. ISSN: 0126-6705 (print).eISSN: 2180-4206.