Yulastri, Y., E. Madona, A. Nasution, and M. Irmansyah. “The Elderly Alzheimer Patient’s Portable Tools for Position Detection With SMS Notifications”. Indonesian Journal of Electronics, Electromedical Engineering, and Medical Informatics, Vol. 3, no. 4, Nov. 2021, doi:10.35882/ijeeemi.v3i4.5.