Yudistira, I., N. Rohman, M. F. F. Mardianto, and Kuzairi. “Comparison Modeling of the Number Population Who Have Been Vaccined in East Java Using the Biresponse Fourier Series Estimator Method With the Trend Function”. Journal Focus Action of Research Mathematic (Factor M), vol. 6, no. 1, June 2023, pp. 37-48, doi:10.30762/factor_m.v6i1.685.