Groeller, H., Davis, G. M., Bennett, G., & Calvert, D. (2007). Intense Physical Training Modifies Intrinsic Heart Rate And Cardiac Autonomic Modulation. Medicine & Science in Sports & Exercise, 39(5), s169. doi:10.1249/01.mss.0000273622.09569.2f
Groeller, H., Davis, G. M., Bennett, G., & Calvert, D. (2007). Intense Physical Training Modifies Intrinsic Heart Rate And Cardiac Autonomic Modulation. Medicine & Science in Sports & Exercise, 39(5), s169. doi:10.1249/01.mss.0000273622.09569.2f