Authors
Magdalena Koleva
University of Shumen, Faculty of Natural Sciences, Department of Chemistry, Shumen, Bulgaria
Yordanka Stanoeva
Dobrudzha Agricultural Institute, Bulgaria
Albena Ivanova
Technical University of Varna, Varna, Bulgaria
Plamen Chamurliyski
University of Shumen, Faculty of Natural Sciences, Department of Chemistry, Shumen, Bulgaria