Many people contributed (in various forms) to this thesis. They are: Susan Armstrong (ISSCO, Université de Genève), Pierrette Bouillon (ISSCO, Université de Genève), Thierry Etchegoyhen (LATL, Université de Genève), Martin Kay (Xerox), Maghi King (ISSCO, Université de Genève), Henryk Krawczyk (Technical University of Gdańsk), Christopher Laenzlinger (LATL, Université de Genève), Sabine Lehmann (ISSCO, Université de Genève), Jacek Martinek (Poznań University of Technology), Tomasz Obrębski (Poznań University of Technology), Dominique Petitpierre (ISSCO, Université de Genève), Michael Rosner (University of Malta), Graham Russel (ISSCO, Université de Genève), Paweł Siwak (Poznań University of Technology), Stanisław Szejko (Technical University of Gdańsk), Zygmunt Vetulani (Adam Mickiewicz University in Poznań), Bruce W. Watson (Ribbit Software, Canada), Richard E. Watson (Ribbit Software, Canada), Eric Wehrli (LATL, Université de Genève).
I would also like to express my gratitude to the Swiss Federal Scholarship Commission for providing me with a scholarship that covered my stay at ISSCO, Geneva, and to the Faculty of Electronics, Telecommunications and Informatics of the Technical University of Gdańsk for supporting my research with grants.