A. Frantsuz А. Й. Ф. /; M. Korinnyj М. М. К. /. Theoretical and Legal Research of the Position and Role of the Proto-Bulgarians in the Ethnogenesis of the Medieval Ukrainian Nationality, Establishing Its Statehood, Law, Language and Culture (IV-XI Centuries). Part ІІ. lbku 2018, No. 30, 5-18.