RT Journal Article SR Electronic T1 Four thoracic cavity compartments caused by bilateral bifid intrathoracic rib JF Thorax JO Thorax FD BMJ Publishing Group Ltd and British Thoracic Society SP 528 OP 529 DO 10.1136/thoraxjnl-2020-214537 VO 75 IS 6 A1 Xue, Xuhong A1 Zhao, Sheng YR 2020 UL http://thorax.bmj.com/content/75/6/528.abstract AB