Gudziak, Borys A..
Crisis and reform: the Kijevan Metropolitanate, the Patriarchate of Constantinople, and the genesis of the Union of Brest /
Borys A. Gudziak ; Harvard Ukrainian Research Institute 
. - Cambridge : Harvard University Press,  1998 
. - xv, 489 p.  ill.  23 cm. 
 - Harvard Series in Ukrainian studies .
<br/><label>  ISBN: </label>0-916458-74-1