Poh Thean, Charles Ang, Mohd Shukrimi Awang, and Satriya Sabir Husin Athar. 2018. “Comparison Between High Frequency and Low Frequency Portable Transcutaneous Electrical Nerve Stimulation in Patients With Knee Osteoarthritis: A Prospective Randomized Study”. IIUM Medical Journal Malaysia 17 (1). https://doi.org/10.31436/imjm.v17i1.832.