"Jahresgabe des Kreises graphischer Kunstler und Sammler" Loss and Restitution: The Story of the Grunwald Family Collection. Los Angeles: Hammer Museum, 2017. https://hammer.ucla.edu/collections/grunwald-center-collection/loss-and-restitution-the-story-of-the-grunwald-family-collection/artists/jahresgabe-des-kreises-graphischer-kunstler-und-sammler