Z matrix components, how are they derived ?

hello,
I need to perform a study about the Z matrix, but I can't find how they have derived the existing formulas, any help or reference is very appreciated.
My interest is on Z matrix describing the metal-metal, metal-dielectric,.., interactions

Thanks in advance

Is the Z matrix you are referring to the same as the impedance matrix? If so, this may help: https://en.wikipedia.org/wiki/Impedance_parameters

Thank you very much!
I need in my study to refer to textbooks..
I am more interested in the formulas which express the impedance matrix using the magnetic vector potential and electric scalar potential
Any suggestion is very welcomed