Vasilev, V., and E. Videv. 2017. “OPPORTUNITIES TO IMPROVE THE CHARACTERISTICS OF MANURE LITTER IN POULTRY FARMS: 1. APPLICATION OF BACTERIAL-ENZYMATIC ADDITIVE IN LAYING HENS”. Bulgarian Journal of Animal Husbandry 54 (1): 17-25. https://agriacad.eu/ojs/index.php/bjah/article/view/296.