Dr. Barbara Hardtwig. Unpublished opinion. January 26, 1983 [cited in catalogue of 2003 Neumeister sale], dates it about 1805.
Gerd-Helge Vogel and Hans-Juergen Moesch in Out into Nature: The Dawn of Plein-Air Painting in Germany, 1820–1850. Exh. cat., Katrin Bellinger at Colnaghi. London, 2003, pp. 15, 44–45, no. 14, ill. (color), misidentifies town as Genzano; notes that this sketch "emulates the 'beau ideal' of English watercolours" that the artist admired, notably those by Richard Wilson; observes the faint pencil underdrawing and monochromatic palette.
Esther Bell. "Catalogue Raisonné of the Thaw Collection." Studying Nature: Oil Sketches from the Thaw Collection. Ed. Jennifer Tonkovich. New York, 2011, p. 119, no. 52, ill. (color), calls it "Nemi" and dates it about 1805.
Aurelio Fichter. Gezeichnete Kunst: Der Zeit entflohen. Frankfurt am Main, 2012, p. 23, discusses the painting in connection with a related drawing.