prof. RNDr. Pavel Drabek, DrSc. Univerzitni 22 phone: +420-377 632 601 P.O.Box 314 fax: +420-377 632 602 306 14 Pilsen e-mail: pdrabek@kma.zcu.cz Czech Republic
Milan Kucera, DrSc. Zitna 25 phone: +420-02-2421 3973 115 67 Praha fax: +420-02-2422 7633 Czech Republic e-mail: kucera@math.cas.cz