The most important sources for determining the time of baptism of Vladimir and Rus and their data: (As for the opinion of Professor Sobolevsky) / [N. Levitsky] .- [St. Petersburg: type. Katanskogo and Co., censuses. 1890] .- 186 with. ; 21 cm. - Auth. specified at the end of the text. l. and obl. Bibliogr. in the note.