Fotsing Tetsing, H., Atindogbé, C. and Nkageu, F. 2022. Normalized null hypersurfaces in the Lorentz-Minkowski space satisfying $L_r x =U x +b$. Tamkang Journal of Mathematics. 54, 4 (Aug. 2022), 353–378. DOI:https://doi.org/10.5556/j.tkjm.54.2023.4851.