1. Trakia University,Faculty of Agriculture,Department of Agricultural Engineering,Stara Zagora,Bulgaria
2. Trakia University,Faculty of Agriculture,Department Plant Crops,Stara Zagora,Bulgaria
3. University of Ruse "Angel Kanchev",Faculty of Electrical Engineering, Electronics and Automation,Department of Automation and Mechatronics,Ruse,Bulgaria
4. Trakia University,Faculty of Agriculture,Department of Biochemistry, Microbiology and Physics,Stara Zagora,Bulgaria