Petrov, Ivan. The development of the Bulgarian literary language: from incunabula to first grammars, late fifteenth-early seventeenth century / Ivan N. Petrov ; translated by Marek Majer and Katarzyna Gucio. — 1 online resource. — (Studies in Slavic, Baltic, and Eastern European languages and cultures). — <URL:http://elib.fa.ru/ebsco/2757788.pdf>.