Ardha, Robby Firmansyah, and Mochamad Alfan Rosid. “Registration System With Midtrans Payment Gateway Using Waterfall Method: Sistem Pendaftaran Dengan Midtrans Payment Gateway Menggunakan Metode Waterfall”. Procedia of Engineering and Life Science, vol. 2, no. 2, June 2022, doi:10.21070/pels.v2i2.1297.