Hamilton and DeTurck's short time existence theorem of the Ricci flow states that if $M^n$ is a smooth closed manifold with a $C^{\infty}$ Riemannian metric $g_0$ on $M$, then the Ricci flow on $M$ starting at $g_0$ exists for a short time.
Question: Are there any short time existence results for an initial metric $g_0$ with less regularity (e.g. $C^{k,\alpha}$, Lipschitz, etc)?