Saputri, N. R.; Luthfiyah, S.; Titisari, D.; Utomo, B.; Lusiana, L.; Triwiyanto, T.; Reegu, F. A.; Caesarendra, W. Enhancing the Electrocardiogram Signal Quality by Applying Butterworth Infinite Impulse Response Filter 8th Order. j.electron.electromedical.eng.med.inform 2022, 4, 235–242.