Kim SK, Kang TW, Park DH, Lee JH, , Cynn HS.  Four-Week Comparative Effects of Abdominal Drawing-In and Diaphragmatic Breathing Maneuvers on Abdominal Muscle Thickness, Trunk Control, and Balance in Patients With Chronic Stroke.  Physical Therapy Korea 2017;24:10-20.  https://doi.org/10.12674/ptk.2017.24.3.010