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Katarzyna Kaźmierczak
Poznań University of Life Sciences, Department of Forest Management, Wojska Polskiego 71c, 60-625 Poznań, Poland
Bogna Zawieja
Poznań University of Life Sciences, Department of Mathematical and Statistical Methods, Wojska Polskiego 28, 60-637 Poznań, Poland, phone: +48 61 8487153