Sample size, study length, and inadequate controls were the most common self-acknowledged limitations in manual therapy trials: A methodological review. - Alvarez G; Núñez-Cortés R; Solà I; Sitjà-Rabert M; Fort-Vanmeerhaeghe A; Fernández C; Bonfill X; Urrútia G (Journal of clinical epidemiology, 2021)