Respitawulan, R., Q. Y. . Pangestu, E. Kusniyanti, F. Yuliawan, and P. . Astuti. “On The Adjoint of Bounded Operators On A Semi-Inner Product Space”. Journal of the Indonesian Mathematical Society, vol. 29, no. 3, Nov. 2023, pp. 311-2, doi:10.22342/jims.29.3.1598.311-321.