Sol LeWitt (2006). “Sol LeWitt wall drawing 1176: seven basic colors and all their combinations in a square within a square : for Josef Albers”, Richter Verlag
Michel de Montaigne (1850). “Works, Comprising His Essays, Letters, and Journey Through Germany and Italy: With Notes from All the Commentators, Biographical and Bibliographical Notices &c., &c”, p.215