Michels F, Clockaerts S, Van Der Bauwhede J, Stockmans F, Matricali G. Does subtalar instability really exist? A systematic review. Foot Ankle Surg. 2020 Feb;26(2):119-127. doi: 10.1016/j.fas.2019.02.001. Epub 2019 Feb 18. PMID: 30827926.