M. U. Lumban Tobing, “The Effect Of Giving Exercise Of Passive Range Of Motion (ROM) To The Flexibility Of Knee Joint In Elderly: Subtitle : There is the Effect Of Giving Exercise Of Passive Range Of Motion (ROM) To The Flexibility Of Knee Joint In Elderly”, JKII, vol. 4, no. 2, pp. 41–47, Dec. 2019.