.,Minkin, M.J. (1998) Assessing sequential irregularity of both endocrine and heart rate rhythms. Curr Opin Obstet Gynecol 10:281-291 Popivanov, D., Mineva, A., Dushanova, J. (1998) Tracking EEG signal dynamics during mental tasks. A combined linear/nonlinear approach. IEEE Eng Med Biol 17:89-95 280 HO