Three vectors $\overline{a},\overline{b},\overline{c}$ are such that $\overline{a}\times \overline{b}=3\left(\overline{a}\times \overline{c}\right)$ also both $\overline{a}, \overrightarrow{b}$ are unit vectors and  $\left|\overline{c}\right|=\frac{1}{3},$ if the angle between $\overline{b}$ and $\overline{c}$ is ${60}^{\circ }$ then _______