Study of the ferrodistorsive orbital ordering in NaNiO2 by neutron diffraction and submillimeter wave ESR E. Chappel, M. D. Núñez-Regueiro, G. Chouteau, O. Isnard and C. Darie Eur. Phys. J. B, 17 4 (2000) 615-622 Published online: 15 October 2000 DOI: 10.1007/s100510070099