@article{article301,
  title = {A new approach to the measurement of heart rate in patients with chronic heart failure-Heart rate performance index:  an observational study},
  author = {Akyüz, A. and Alpsoy, Ş. and Çayan  Akkoyun, D. and Güler, N.},
  journal = {The Anatolian Journal of Cardiology},
  year = {2013},
  volume = {13},
  pages = {215-220},
  doi = {10.5152/akd.2013.066}
}