My Ph.D. thesis supervised by J. Zimányi was written in 1981  . It describes a computer simulation of coupled hadronic processes, in particular strange meson and hyperon production in the framework of hadrochemistry developed earlier by J. Zimányi and I. Montvay . The entropy produced due to the approach to chemical equilibrium between the different hadrons is calculated locally in a relativistic hydrodynamical description.
The description of finite volume effects in nucleon - deuteron mixtures are based on an idea of B. Lukács [9, 11] . The effect of a fast expansion of the nuclear fireball on the deuteron - nucleon ratio, when the approach to the chemical equilibrium is slower then its instantaneous shift due to the expansion, is described in the general classifying framework of Asymptotic Hadrochemistry  .
In the first part of my long stay at the University of Giessen (1985 - 1994) I contributed to calculations of photon and meson production in intermediate energy heavy ion collisions by determining relativistic production rates in elementary nucleon - nucleon processes in the framework of different phenomenological hadronic field theories [21, 24 , 26 , 33 , 34] . These rates has been used in collaboration with W. Cassing, U. Mosel, K. Niita A de Paoli and G. Wolf in extended computer simulations which described the heavy ion collisions in the framework of nuclear transport theory. In particular I tutored diplom works in this field ( M. Schäfer, T. Vetter, A. Engel ).
After my return to Budapest (1994) I took part in the development of a new model together with J. Zimányi and P. Lévai. This model is devoted to the description of the hadronization of a quark matter, which is probably formed in heavy-ion experiments at CERN (ALCOR model,  . The starting point in this model a thermalized quark matter without gluons and diquarks. These quarks, also via intermedier creation of diquarks, will be distributed in all possible ways between the two lowest lying mesonic baryonic states.
In the early versions of this model the elementary processes, which produced the hadrons, were calculated in analogy to the nuclear pick-up reaction. This way from a quark and an antiquark a single pion was created and the total momentum was balanced by the medium. Recently we are working in a collaboration with S. Klevansky and P. Rehberg from the MPI Heidelberg on the description of the elementray processes in the framework of the Nambu-Jona-Lasinio model. In this case the hadron formation is accompanied by additional quark antiquark pair creations.