found: Claus, H. Karel Appel, 1962.
found: Primal images, 1974:p. 6 (Karel Appel, b. 1921 in Amsterdam, The Netherlands; lives in France and the United States; painter and sculptor)
found: Appel, 1950:cover (C.K. Appel)
found: Info. from J.N. Houterman, June 19, 2000(Christiaan Karel Appel; b. 1921)
found: German Wikipedia WWW site, May 5, 2006(Karel Appel; b. Christiaan Karel Appel, Apr. 25, 1921, Amsterdam; d. May 3, 2006, Zürich; Dutch painter and co-founder of the CoBrA artists group)
found: Karel Apel, 2004:t.p.
found: Information from 678 converted Dec. 19, 2014(painter; 25th April)