H. F. Laia and Zahedi, “Implementation of Autoregresssive Integrated Moving Average (ARIMA) on Forecasting the Number of Positive Cases of Covid-19 in North Sumatra on September 2021: Implementasi Autoregresssive Integrated Moving Average (ARIMA) Pada Peramalan Jumlah Kasus Positif Covid-19 Sumatera Utara Pada September 2021”, J. of Maths Tech and Edu, vol. 1, no. 3, pp. 229-241, Jun. 2022.