1. Fachbereich Chemie, Philipps‐Universität Marburg, Hans‐Meerwein‐Strasse, 35032 Marburg‐Lahn, Germany, Fax: (internat.) +49‐6421/282‐5642
2. Chemistry Department, Moscow State University, 234 Leninskie Gory, 119899 Moscow, Russia, Fax: (internat.) +7‐095/932‐8846
3. Tomsk Pedagogical University, Komsomolskii 75, 634041 Tomsk, Russia