er, J., Holmes, P. (1983): Nonlinear Oscillations, Dynamical Systems and Bifurcations of Vector Fields. Springer. N.Y. Guillemin, R.C., Brazeau, P., Briskin, A., Mandell, A.J. (1983) Evidence for synergetic dynamics in a mammalian pituitary cell perfusion system in (ed. E.Basar, H. Flohr, H. Haken, A.J.