Utami, Indrianti Putri. “Praktik Jual Beli Pre Order Dengan Sistem Online: Practice of Pre-Order Buying and Selling With Online System”. Al-Muamalat: Jurnal Ekonomi Syariah 9, no. 1 (August 4, 2022): 20–28. Accessed December 8, 2025. https://journal.uinsgd.ac.id/index.php/mua/article/view/14045.