Inelastic neutron scattering investigation of the magnetic excitations in the helimagnetic state of NiBr2 L.P. Régnault, J. Rossat-Mignod, A. Adam, D. Billerey et C. Terrier J. Phys. France, 43 8 (1982) 1283-1290 DOI: 10.1051/jphys:019820043080128300