BIM versus Finite Element

[J Stasko]

I have been looking at Anastasis C. Polycarpou's book, Introduction to the Finite Element Method in Electromagnetics, and I understand it well so far, I'm just starting the second half.

I have also been looking at Johann Cervenka's dissertation which can be found here, http://www.iue.tuwien.ac.at/phd/cervenka/diss.html .  

He mentions that there are three different techniques, finite element, finite difference, and box integration.  He does mention that finite elements use Ansatzfunktionen, which is covered in Polycarpou's work, and I don't see much mention of it in the BIM software.  I'm beginning to suspect that BIM is a special case of FEM, where the Ansatzfunktionen chosen are the set with a polynomial of degree one (as Polycarpou describes in section 1.5).

Does anyone has a reference which explicitly compares the three?