Muhamad, Sabat, and Twana Nasih Ahmed. “Image-Based Processing of Paper Currency Recognition and Fake Identification: A Review”. Technium: Romanian Journal of Applied Sciences and Technology, vol. 3, no. 7, Aug. 2021, pp. 46-63, https://techniumscience.com.techniumscience.pluscommunication.eu/index.php/technium/article/view/4378.