Air trapping: The major factor limiting diaphragm mobility in chronic obstructive pulmonary disease patients - Yamaguti, Wellington Pereira dos; Paulin, Elaine; Shibao, Simone; Chammas, Maria Cristina; Salge, João Marcos; Ribeiro, Marcos; Cukier, Alberto; Carvalho, Celso Ricardo Fernandes (Respirology, 2008)