Occult pneumothoraces in children with blunt torso trauma. - Lee LK; Rogers AJ; Ehrlich PF; Kwok M; Sokolove PE; Blumberg S; Kooistra J; Olsen CS; Wootton-Gorges S; Cooper A; Kuppermann N; Holmes JF (Academic emergency medicine : official journal of the Society for Academic Emergency Medicine, 2014)