Appel, K., Visser, H. d., Hagenberg, R., & Kuspit, D. B. (1990). Karel Appel: The Complete Sculptures : 1936-1990 / Edited by Harriet de Visser and Roland Hagenberg. Ed. Lafayette.
Lua i Stíl Chicago (17ú heag.)Appel, Karel, Harriet de Visser, Roland Hagenberg, agus Donald B. Kuspit. Karel Appel: The Complete Sculptures : 1936-1990 / Edited by Harriet De Visser and Roland Hagenberg. New York: Ed. Lafayette, 1990.
Lua MLA (8ú heag.)Appel, Karel, et al. Karel Appel: The Complete Sculptures : 1936-1990 / Edited by Harriet De Visser and Roland Hagenberg. Ed. Lafayette, 1990.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.