Biconservative hypersurfaces in space forms ${\bar{M}}^{\text{lowercase}n+1}(\text{lowercase}c)$

In this paper we study biconservative hypersurfaces $M$ in space forms ${\bar{M}}^{n+1}(c)$ with four distinct principal curvatures whose second fundamental form has constant norm. We prove that every such hypersurface has constant mean curvature and constant scalar curvature.