Setyadi, H., Supriyanta, S. and Nurohim, G. 2024. Improving Junk Sale and Purchase Transactions Using a Spiral Model-Based System. Journal of Information Systems and Informatics. 6, 4 (Dec. 2024), 2237-2254. DOI:https://doi.org/10.51519/journalisi.v6i4.871.