File:Pablo Picasso, 1906, Seated Male Nude (Homme nu assis), oil on canvas, 34.9 x 24.1 cm, Barnes Foundation.jpg

Published in 1920
[https://archive.org/stream/derwegzumkubismu00kahnuoft#page/n77/mode/2up Daniel Henry Kahnweiler, Der Weg zum Kubismus. Published 1920 by Delphin in München. Written in German]