Erikson , U., A. Hallén, G. Helmius, S.-O. Nyström, and G. Ruhn. “Coronary By-Pass Operation—Graft and Left Ventricular Function”. Upsala Journal of Medical Sciences, vol. 85, no. 1, Mar. 1980, pp. 84-93, doi:10.3109/03009738009179175.