The Artist's Sister, Marie von Kalckreuth by Galerie Gerda Bassenge, Anne Koenigs, Ailsa Mellon Bruce Fund, Bellinger, Katrin, Ms., Leopold von Kalckreuth, Stiftung Ratjen, Kornelia van Eyck Koenigs, C.G. Boerner LLC, Wolfgang Ratjen — VisualArtsDB

The Artist's Sister, Marie von Kalckreuth by Galerie Gerda Bassenge, Anne Koenigs, Ailsa Mellon Bruce Fund, Bellinger, Katrin, Ms., Leopold von Kalckreuth, Stiftung Ratjen, Kornelia van Eyck Koenigs, C.G. Boerner LLC, Wolfgang Ratjen — VisualArtsDB