Zhu, Mingjie, Moustafa A. Maher, Wanjun Gu, Kenneth J. Hunt, Mark S. Myerson, and Shuyuan Li. 2023. “Content Validation of the Progressive Collapsing Foot Deformity Classification”. Journal of the Foot & Ankle 17 (3):156-62. https://doi.org/10.30795/jfootankle.2023.v17.1731.