M. Karvonen, K. Kentala, O. Mustala: The effects of training heart rate: a longitudinal study. In: Annales Medicinae Experimentalis et Biologiae Fenniae 35, 1957,
M. Karvonen, K. Kentala, O. Mustala: The effects of training heart rate: a longitudinal study. In: Annales Medicinae Experimentalis et Biologiae Fenniae 35, 1957,