Murti, A.S., 		Manuaba, I.B.G., AND 		Arjana, I.G.D.
" OPTIMASI UNIT PLTU BERBAHAN BAKAR BATUBARA MENGGUNAKAN METODE LAGRANGE DI PT. INDONESIA POWER UP SURALAYA" <em>Jurnal SPEKTRUM</em> [Online], Volume 7 Number 1 (7 March 2020)