Talia, A., Lasker Pangarapan Sinaga, and Lasker Pangarapan Sinaga. “Optimization of the Electricity Economics System (EES) in Supporting National Energy Policy Using a Tri-Level Programming Approach”. JURNAL ILMIAH MATEMATIKA DAN TERAPAN, Vol. 23, no. 1, June 2026, pp. 26 -40, doi:10.22487/2540766X.2026.v23.i1.18081.