ERSIGHT_013794 Zipf, G.K. (1949) Human Behavior and the Principal of Least Effort. Addison- Wesley, N.Y. Zwiener, U., Hoyer, D., Bauer, R., Luthke, B., Walter, B., Schmidt, K., Hallmeyer, S.,Kratzsch, B., Eiselt, M.(1996) Deterministic--chaotic and periodic properties of heart rate and arterial pressure fluctuations and the