Letters of the Archbishop-Elector Joseph Clemens of Cologne to Robert de Cotte (1712 - 1720) ; with supplementary letters from the architect Guillaume d'Hauberat to de Cotte (1716 - 1721) - Joseph Clemens Köln, Erzbischof 1671-1723; Hauberat, Guillaume d' 1680-1749 (State University, 1956)