Shahi CN, Rathore SS, Wang Y, Thakur R, Wu WC, Lewis JM, Petrillo MK, Radford MJ, Krumholz HM. Quality of care among elderly patients hospitalized with unstable angina. Am Heart J. 2001 Aug;142(2):263–70. doi: 10.1067/mhj.2001.116477. PMID: 11479465.