Narayan Mohapatra, B., R. Kumari Mohapatra, M. Mirpagar, and A. Quershi. “Ultrasonic Based Easy Parking System Based on Microcontroller”. International Journal of Innovative Technology and Interdisciplinary Sciences, vol. 3, no. 2, Apr. 2020, pp. 429-34, doi:10.15157/IJITIS.2020.3.2.429-434.