Pastva AM, Duncan PW, Reeves GR, Nelson MB, Whellan DJ, O'Connor CM, Eggebeen JD, Hewston LA, Taylor KM, Mentz RJ, Rosenberg PB, Kitzman DW. Strategies for supporting intervention fidelity in the rehabilitation therapy in older acute heart failure patients (REHAB-HF) trial. Contemp Clin Trials. 2018 01; 64:118-127.