multivariate normal - Matrix Derivatives

I'm trying to calculate a MLE and was wondering if anyone had a reference or could help me with derivatives involving matrices: $$ \frac{\partial}{\partial \sigma^2} \sum\limits_{k = 1}^{K} (Y_k - \mu)^T\frac{1}{\sigma^2}(I_n - \frac{\tau^2}{\sigma^2 + n\tau^2}1_n)(Y_k - \mu) $$or $$ \frac{\partial}{\partial \sigma^2} \sum\limits_{k = 1}^{K} (Y_k - \mu)^T\frac{1}{\sigma^2}(I_n - \frac{\tau^2}{\lambda}1_n)(Y_k - \mu) $$where $$ \lambda = \sigma^2 + n\tau^2$$Basically this is the last term in a log-likelihood of a multivariate normal, $$MVN(\mu,...Read more