Setyadi, Heribertus Ary, Supriyanta Supriyanta, and Galih Setiawan Nurohim. 2024. “Improving Junk Sale and Purchase Transactions Using a Spiral Model-Based System”. Journal of Information Systems and Informatics 6 (4): 2237-54. https://doi.org/10.51519/journalisi.v6i4.871.