A perturbative method for calculating the impedance of coils on laminated ferromagnetic cores. Maximov, Serguei, Castillo, Allen A., Venegas, Vicente, Guardado, José L., Melgoza, Enrique (2010) Mathematical Problems in Engineering
Analysis of an algorithm for computing electromagnetic Bloch modes using Nedelec spaces. Dobson, D.C., Pasciak, J.E. (2001) Computational Methods in Applied Mathematics