Richard William Hubbard. Richard William Hubbard letter to unidentified recipient, 1857 February 26. Charles Henry Hart autograph collection, 1731-1918. Archives of American Art, Smithsonian Institution.
Sanford Robinson Gifford. Sanford Robinson Gifford, Montreal, Canada letter to Richard William Hubbard, 1888 August 05. Charles Henry Hart autograph collection, 1731-1918. Archives of American Art, Smithsonian Institution.
George Gardner Rockwood and Napoleon Sarony. Richard William Hubbard, ca. 1865-1867. [Artists' portraits from Henry Tuckerman's Book of the Artists...], circa 1865]-1867, undated. Archives of American Art, Smithsonian Institution.