Gutknecht, K. (1979). Gerhard Marcks.
Lua i Stíl Chicago (17ú heag.)Gutknecht, Klaus. Gerhard Marcks. Rostock, 1979.
Lua MLA (8ú heag.)Gutknecht, Klaus. Gerhard Marcks. 1979.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.