RT Journal Article SR Electronic T1 Westermark’s sign in submassive pulmonary embolism JF Emergency Medicine Journal JO Emerg Med J FD BMJ Publishing Group Ltd and the British Association for Accident & Emergency Medicine SP 282 OP 282 DO 10.1136/emj.2008.060087 VO 26 IS 4 A1 J W Booth A1 R D Rakhit A1 I Cropley A1 J R Hurst YR 2009 UL http://emj.bmj.com/content/26/4/282.abstract AB