Paul Klee. The Sublime Side postcard for "Bauhaus Exhibition Weimar 1923" (Die erhabene Seite Postkarte zur "Bauhaus-Ausstellung Weimar 1923"). 1923 | MoMA
Paul Klee | Untitled | The Metropolitan Museum of Art
Paul Klee: Making Visible – review | Paul Klee | The Guardian
Paul Klee (1879 - 1940) : Free Download, Borrow, and Streaming : Internet Archive
Paul Klee | Clarification | The Metropolitan Museum of Art