Proceedings of the International Congress Congress Commemorating the Millennium of Christianity in Rus'-Ukraine / general editors: Omeljan Pritsak and Ihor Sevcenko ; with assistance of Miroslav Labunka. - Commemorative edition. - Cambridge : Harvard University, Ukranian Research Institute, 1990. - 894 p. - ( Harvard Ukrainian studies ;vol. 12-13, 1988-1989: )