Alfred Robaut. L'Œuvre de Corot: Catalogue raisonné et illustré. [reprint 1965]. Paris, 1905, vol. 2, pp. 162–63, no. 454, ill., vol. 4, p. 203, calls it "Collines de Genzano" and dates it 1843.
André Jullien and Renée Jullien. "Corot dans les Castelli Romani." Gazette des beaux-arts, 6th ser., 110 (October 1987), pp. 124–25, 130 n. 44, identify the site where this sketch and two drawings now in the Musée du Louvre, Paris (inv. RF 9026 recto [Robaut 1905, no. 2772 recto] and inv. RF 9029 verso [Robaut 1905, no. 2786 recto]) were executed.
Michael Pantazzi in Corot. Exh. cat., The Metropolitan Museum of Art. New York, 1996, p. 196 under no. 82 and p. 199 under no. 84, erroneously states that the sketch is painted on wood and dated June 26, 1843.
Cara Dufour Denison in The Thaw Collection: Master Drawings and Oil Sketches, Acquisitions Since 1994. Exh. cat., Pierpont Morgan Library. New York, 2002, pp. 200–201, no. 92, ill. (color), asserts that this sketch was painted after "View of Genzano with Rider and Peasant" (MMA 2009.400.30).
Kasper Monrad. Turner and Romantic Nature. Exh. cat., Statens Museum for Kunst. Copenhagen, 2004, pp. 91, 95, 244, no. 51, ill. (color), disagrees with Ref. Denison 2002, citing Philip Conisbee's argument that this sketch appears to have been used as a study for MMA 2009.400.30.
Asher E. Miller in "Recent Acquisitions, A Selection: 2008–2010." Metropolitan Museum of Art Bulletin 68 (Fall 2010), pp. 47–49, ill. (color).
John House. "Impressionism and the Open-Air Oil Sketch." Studying Nature: Oil Sketches from the Thaw Collection. Ed. Jennifer Tonkovich. New York, 2011, pp. 91–92, fig. 75B (color), presumes that "this was the étude that served as the starting point" of MMA 2009.400.30, describing the latter as "the more elaborated picture".
Esther Bell. "Catalogue Raisonné of the Thaw Collection." Studying Nature: Oil Sketches from the Thaw Collection. Ed. Jennifer Tonkovich. New York, 2011, p. 111, no. 29, ill. (color), calls it "View of Genzano".