Relative coronary flow reserve: a new index for improved correlation with stress thallium-201 myocardial perfusion imaging in assessment of intermediate and severe coronary artery stenoses - Voudris, V; Avramidis, D; Papadakis, M.; Malakos, J; Manginas, A.; Patsilinakos, S; Kolovou, G; Cokkinos, D.V. (EUROPEAN HEART JOURNAL, 2001)