T. Nikolova, K., and D. T. Boyadzhiev. “CLASSIFICATION OF DIFFERENT TYPES BEE HONEY ACCORDING TO PHYSICO-CHEMICAL CHARACTERISTICS”. Ann. Sofia Univ. Fac. Math. And Inf., vol. 102, Dec. 2015, pp. 281-7, https://ftl5.uni-sofia.bg/index.php/fmi/article/view/75.