Vaughan, W., Börsch-Supan, H., & Neidhardt, H. J. (1972). Caspar David Friedrich 1774-1840: Romantic landscape painting in Dresden.
Lua i Stíl Chicago (17ú heag.)Vaughan, William, Helmut Börsch-Supan, agus Hans Joachim Neidhardt. Caspar David Friedrich 1774-1840: Romantic Landscape Painting in Dresden. London, 1972.
Lua MLA (8ú heag.)Vaughan, William, et al. Caspar David Friedrich 1774-1840: Romantic Landscape Painting in Dresden. 1972.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.