Ravindran, Darrshiny, and Nur Anida Jumadi. “Development of IoT-Based Heart Rate and Oxygen Saturation Alert System for COVID-19 Wards”. Evolution in Electrical and Electronic Engineering 3, no. 2 (November 14, 2022): 211–222. Accessed July 18, 2024. https://penerbit.uthm.edu.my/periodicals/index.php/eeee/article/view/8595.