Annisatul Ma’rifah, NIM.: 16610014 (2023) PENENTUAN SOLUSI AWAL MASALAH TRANSPORTASI DENGAN METODE WEIGHTED OPPORTUNITY COST, SEQUENTIALLY UPDATED WEIGHTED OPPORTUNITY COST DAN MODIFIED VOGEL’S APPROXIMATION METHOD (Studi Kasus : PERUM BULOG SUB DIVRE MEDAN). Skripsi thesis, UIN SUNAN KALIJAGA YOGYAKARTA.