Butarbutar, John, Yeremia Tatang, Hori Hariyanto, Edu Tehupeory, and Ludwig A. Pontoh. “Distance Between Parapatellar Portal and Intra-Articular Space for Needle Positioning in Knee Osteoarthritis”. Medical Journal of Indonesia 22, no. 2 (June 1, 2013): 83-7. Accessed January 21, 2022. http://mji.ui.ac.id/journal/index.php/mji/article/view/533.