Institution: | 1. Department of Mathematics , Tadeusz Kotarbiński Pedagogical University , Zielona G?ra, 65069, Poland;2. Department of Mathematical and Statistical Methods , Academy of Agriculture , Poznań, 60637, Poland;3. Department of Statistics , University of Dortmund , P.O. Box 50 05 00,4600 Dortmund, Federal Republic of Germany |