[4] Task Force of the European Society of Cardiology the North American Society of Pacing Electrophysiology, Heart Rate Variability, Standards of Measurement, Physiological Interpretation, and Clinical Use, Circ., vol.93, No.5, pp.1043-1065, 1996.
[5] A. Nakata, T. Haratani, M. Takahashi, N. Kawakami, H. Arito, F. Kobayashi, S. Araki, Job stress, social support, and prevalence of insomnia in a population of Japanese daytime workers, Soc. Sci. Med., vol.59, Issue8, pp,1719-1730, October 2004.