Authors
Pavol Porvaz
National Agricultural and Food Centre-Research Institute of Plant Production, Institute of Agroecology, Michalovce, Slovak Republic
Ivan Kron
Training & Consulting Ltd Žilina, Slovak Republic
Štefan Tóth
National Agricultural and Food Centre-Research Institute of Plant Production, Institute of Agroecology, Michalovce, Slovak Republic
Antonín Kintl
Agricultural Research, Ltd, Troubsko, Czech Republic