1. and in: and (Eds) Man and His Ecosystem. Proc. 8th World Clean Air Congress, The Hague, The Netherlands, Sep 11-15, 1989, Volume 1, Elsevier Science Publishers B. V., Amsterdam (1989).
2. and Second Seminar “Quo Vadis Chromatographia?”, Versailles, Dec 6-7, 1988.