Yusmansyah , Erfizal Fikri, Syafrizal Martinis, Agnesia Candra Sulyani, Hasna Nurhasanah, and R. Danisworo Wicaksono Rivianto. 2023. “Measuring Internal Customer Satisfaction Using Net Promoter Score: Case Study on Digital Product”. International Journal of Membrane Science and Technology 10 (2):3089-97. https://doi.org/10.15379/ijmst.v10i2.3053.