BadamKhorl Y, Kim T, Park H.  Effect on the Activity and Ratio of the Serratus Anterior, Pectoralis Major, and Upper Trapezius according to the Angle of Abduction and External Weight During Shoulder Protraction Exercise for Winged Scapular Subjects.  Physical Therapy Korea 2019;26:1-10.  https://doi.org/10.12674/ptk.2019.26.3.001