Grant C, Becker P, Viljoen M. Determining heart rate variation: a comparison between direct results from V6 of the ECG and time domain, frequency domain and non-liniar analysis. SATNT [Internet]. 22Sep.2006 [cited 4May2024];25(2):67-1. Available from: http://satnt.ac.za/index.php/satnt/article/view/155