Matthew RP, Seko S, Kurillo G, Bajcsy R, Cheng L, Han JJ, Lotz J. Reachable Workspace and Proximal Function Measures for Quantifying Upper Limb Motion. IEEE journal of biomedical and health informatics. 2020 Apr 23;24(11):3285-94, doi: 10.1109/JBHI.2020.2989722.