In general I find that working with mathematics as auxiliary to any field is hard when you do not get to practice it every day. In these cases I have found the

In general I find that working with mathematics as auxiliary to any field is hard when you do not get to practice it every day. In these cases I have found the matrix cookbook [1] to be very helpful as it serves as a quick reference. [1] http://www2.imm.dtu.dk/pubdb/views/edoc_download.php/3274/pdf/imm3274.pdf http://www2.imm.dtu.dk/pubdb/views/edoc_download.php/3274/pd...