Woman, Robert Frederick Blum, 1880,Smithsonian: Cooper Hewitt, Smithsonian Design Museum
https://collection.cooperhewitt.org/view/objects/asitem/id/12884
Man and Woman, Robert Frederick Blum, 1881–1882,Smithsonian: Cooper Hewitt, Smithsonian Design Museum
https://collection.cooperhewitt.org/view/objects/asitem/id/13022