Luthfiyah, Sari, et al. “Use Chest Vibrator to Prevent Pulmonary Infection in Patients With COPD ”. Indonesian Journal of Electronics, Electromedical Engineering, and Medical Informatics, vol. 1, no. 2, Aug. 2025, pp. 81-84, https://doi.org/10.35882/ijeeemi.v1i2.255.