Citation: Alario-Franco, M.A.; Grey, I.E.; Labeau, M.; Joubert, J.C.; Vincent, H. (1982). Structural studies on a-cation-deficient perovskite-related phases. I. Th Nb4 O12. Thorium vacancy ordering in slow-cooled samples. Acta Crystallographica A (24,1968-38,1982), 38, pp. 177-186.