# Two-Port Network with Sources. How to cascade the Chain Matrix?

From EMC Analysis Methods and Computational Models by Tesche on page 61 we can see a chain matrix representation of two-port networks with sources (as seem in the attached image). Lets assume I have got a two port before the section with the source and one afterwards. Usually I would multiply the matrices and receive a two-port that represents the complete section. How is this done with the matrix listed by Tesche? I thought that I can not add the vector to the matrix and therefore I dont know how to multiply the 3 individual matrices to get the complete representation.