Taking derivatives of complex matrix expressions

I have to take derivative of the following expression (For example):

$$\frac{\partial \left( -x^T QBL y \right)}{\partial L}$$

where $x,y$ vectors and $Q,B,L$ are matrices with arbitrary (proper) dimensions (this is not necessarily to be a quadratic form - think the most general case). This is only one case I came accross, in general I want to become comfortable for this type of derivatives. Can somebody point a reference?

And also if one show how this derivative can be taken, I will be very happy. Thanks in advance!

via Recent Questions - Mathematics - Stack Exchange http://math.stackexchange.com/questions/291293/taking-derivatives-of-complex-matrix-expressions