{{Cite journal| doi = 10.1364/OL.44.001104| volume = 44| issue = 5| pages = 1104–1107| last1 = Zimmer| first1 = A.| last2 = Gilliot| first2 = M.| last3 = Tresse| first3 = M.| last4 = Broch| first4 = L.| last5 = Tillous| first5 = K.E.| last6 = Boulanger| first6 = C.| last7 = Stein| first7 = N.| last8 = Horwat| first8 = D.| title = Coloration mechanism of electrochromic Na x WO 3 thin films| journal = Optics Letters| date = 2019}}