Otten & Otten collection
ot-art
Willem Otten Instagram
wooden-bird
wooden-bird Instagram
Museum van de Geest (Netherlands)
Museum Dr. Guislain Gent (Belgium)
Museum Charlotte Zander (Germany)
Muzeum Ziemi Chelmskiej (Poland)
Muzeum Śląski Katowice (Poland)
Muzeum Jacka Malczewskiego w Radomiu (Poland)
Panstwowe muzeum ethnograficzne Warszawa (Poland)
Outsider art museum (Russia)
Collection de l’art brut Lausanne (Switzerland)
Museum of Amerian folk art (USA)
Anthony Petullo Art Collection (USA)
Film by the collectors couple Horst en Gisela Riedel (German language 9,45 minutes)