Finiteness of physical measures for diffeomorphisms with multi 1-D centers

Let $f$ be a $C^2$ diffeomorphism on compact Riemannian manifold $M$ with partially hyperbolic splitting $$TM=E^u\oplus E_1^c\oplus\cdots\oplus E_k^c \oplus E^s,$$ where $E^u$ is uniformly expanding, $E^s$ is uniformly contracting, and ${\rm dim}E_i^c=1,~ 1\le i \le k, ~k\ge 1$. We prove the finiteness of ergodic physical(SRB) measures of $f$ under the hyperbolicity of Gibbs $u$-states.