Robert Indiana, The American Hay Company, 1962, Conté crayon frottage on paper, The Museum of Modern Art, New York. https://dartabase.art/cite/moma/35281

Robert Indiana, Square (from 'Polygons' series), 1975, Screenprint on paper, Queensland Art Gallery and Gallery of Modern Art, Brisbane. https://dartabase.art/cite/qagoma/4723