1. U Rajendra Acharya, K Paul Joseph, Natarajan Kannathal, Choo Min Lim, and Jasjit S Suri. 2006. Heart rate variability: a review. Medical and biological engineering and computing 44, 12 (2006), 1031--1051.
2. John Allen. 2007. Photoplethysmography and its application in clinical physiological measurement. Physiological measurement 28, 3 (2007).
3. Ahmed Alqaraawi, Ahmad Alwosheel, and Amr Alasaad. 2016. Heart rate variability estimation in photoplethysmography signals using Bayesian learning approach. Healthcare technology letters 3, 2 (2016).
4. Shikder Shafiul Bashar, Md Sazal Miah, AHM Zadidul Karim, Md Abdullah Al Mahmud, and Zahid Hasan. 2019. A machine learning approach for heart rate estimation from PPG signal using random forest regression algorithm. In 2019 International Conference on Electrical, Computer and Communication Engineering (ECCE). IEEE, 1--5.
5. James Bergstra and Yoshua Bengio. 2012. Random search for hyperparameter optimization. J. of machine learning research 13, 2 (2012).