The effectiveness of additional core stability exercises in improving dynamic sitting balance, gait and functional rehabilitation for subacute stroke patients (CORE-Trial): Study protocol for a randomized controlled trial - Cabanas-Valdés, R; Boix-Sala, L; Grau-Pellicer, M; Guzmán-Bernal, J A; Caballero-Gómez, F M; Urrútia, G (Int J Environ Res Public Health, 2021)