How to calculate this partial derivative?

given the function:

${v}_{h}={[\sum _{i=1}^{N}{r}_{h,i}\cdot {w}_{h,i}-\frac{1}{T}\sum _{t=1}^{T}\sum _{i=1}^{N}{r}_{t,i}{w}_{t,i}]}^{2}$

I would like to compute the following:

$\frac{\mathrm{\partial}{v}_{h}}{\mathrm{\partial}{w}_{h}}=\phantom{\rule{thickmathspace}{0ex}}?$

$\frac{\mathrm{\partial}{v}_{h}}{\mathrm{\partial}{r}_{h}}=\phantom{\rule{thickmathspace}{0ex}}?$

$\frac{\mathrm{\partial}{v}_{h}}{\mathrm{\partial}{w}_{h}\mathrm{\partial}{r}_{h}}=\phantom{\rule{thickmathspace}{0ex}}?$

The problem for me is the double sum in the second term. Example of the function with $N=2$ and $T=2$ for $t=1$:

${v}_{1}={[({r}_{1,1}\cdot {w}_{1,1}+{r}_{1,2}\cdot {w}_{1,2})-\frac{1}{2}({r}_{1,1}\cdot {w}_{1,1}+{r}_{1,2}\cdot {w}_{1,2}+{r}_{2,1}\cdot {w}_{2,1}+{r}_{2,2}\cdot {w}_{2,2})]}^{2}$

given the function:

${v}_{h}={[\sum _{i=1}^{N}{r}_{h,i}\cdot {w}_{h,i}-\frac{1}{T}\sum _{t=1}^{T}\sum _{i=1}^{N}{r}_{t,i}{w}_{t,i}]}^{2}$

I would like to compute the following:

$\frac{\mathrm{\partial}{v}_{h}}{\mathrm{\partial}{w}_{h}}=\phantom{\rule{thickmathspace}{0ex}}?$

$\frac{\mathrm{\partial}{v}_{h}}{\mathrm{\partial}{r}_{h}}=\phantom{\rule{thickmathspace}{0ex}}?$

$\frac{\mathrm{\partial}{v}_{h}}{\mathrm{\partial}{w}_{h}\mathrm{\partial}{r}_{h}}=\phantom{\rule{thickmathspace}{0ex}}?$

The problem for me is the double sum in the second term. Example of the function with $N=2$ and $T=2$ for $t=1$:

${v}_{1}={[({r}_{1,1}\cdot {w}_{1,1}+{r}_{1,2}\cdot {w}_{1,2})-\frac{1}{2}({r}_{1,1}\cdot {w}_{1,1}+{r}_{1,2}\cdot {w}_{1,2}+{r}_{2,1}\cdot {w}_{2,1}+{r}_{2,2}\cdot {w}_{2,2})]}^{2}$