Sahlén A, Wu E, Rück A, Hagerman I, Förstedt G, Sylvén C, Berglund M, Jernberg T. Relation between N-terminal pro-brain natriuretic peptide levels and response to enhanced external counterpulsation in chronic angina pectoris. Coron Artery Dis. 2014 Jan;25(1):45–51. doi: 10.1097/mca.0000000000000057. PMID: 24217402.