Furqorina, R., and M. I. . Firdaus. “Achievement of BLU Financial Performance in the Field of Education Services before and During the COVID-19 Pandemic”. Jurnal Mantik, vol. 7, no. 2, Aug. 2023, pp. 1148-55, https://www.ejournal.iocscience.org/index.php/mantik/article/view/4022.