TY - JOUR TI - Could decreased vitamin D levels be related with impaired cardiac autonomic functions in patients with chronic heart failure: an observational study AU - Çetin, M. AU - Kozdağ, G. AU - Ural, D. AU - Kahraman, G. AU - Yılmaz, İ. AU - Akay, Y. AU - Onuk, R. AU - Dursun, N. JO - The Anatolian Journal of Cardiology PY - 2014 VL - 14 SP - 434 EP - 441 DO - 10.5152/akd.2014.4869 ER -