Hadamard, J. (1898) Les surfaces a courbures opposees et leur lignes geodesic. J. Math. Pures. Appl. 4:27-73 263 HOUSE_OVERSIGHT_013763 Hagerman, |.,Berglund, M., Lorin, M., Nowak, J., Sylven, C.(1996) Chaos-related deterministic regulation of heart rate variability in time- and frequency domains: effects