@misc{Abraham_Władysław_(1860-1941)_Gniezno,
 author={Abraham, Władysław (1860-1941)},
 howpublished={online},
 publisher={Polska Akademia Umiejętności (1919-1952)},
 language={Polish},
 title={Gniezno i Magdeburg},
 type={book},
 keywords={Poland, Germany, christianity, church history, Middle Ages, international relations},
}