Nicholas Copernicus Univ., Nicholas Copernicus Univ., Dep. of Slavic languages and the East Central European center Columbia Univ., 2001 г. ISBN 83-231-1246-0
Nicholas Copernicus Univ., Nicholas Copernicus Univ., Dep. of Slavic languages and the East Central European center Columbia Univ., 2001 г. ISBN 83-231-1246-0