Fiep Westendorp (1916-2004) is one of the best known Dutch children's illustrators. These illustrations are from a collection I bought in the Netherlands, Jip en Janneke, by Annie M.G. Schmidt and Fiep Westendorp, printed by Quirdo. The site is in Dutch, but you can see more about Fiep here, at the official site for her. The English version didn't come up properly for me, but maybe it'll work for you.