assioui, F.E., Allilaire, F., Muller, J. (1996) Depression as a dynamic disease. Biol. Psychiat. 39:991-999 Pijn, J., Velis, D., van der Heyden, M., DeGoede, J., van Veelen, C.W., Lopes da Silva, F. (1997): Nonlinear dynamics of epileptic seizures on basis of intracranial EEG recordings. Brain Topogr. 9: