The authors present a new formulation of the integral equation of the measured equation of invariance (MEI) as a confined field integral equation discretised by the method of moments, in which the use of numerically derived testing functions results in an approximately sparse linear system with storage memory requirements and a CPU time for computing the matrix coefficients proportional to the number of unknowns.
Rius, J., Parron, J., Ubeda, E., Mosig, J. Integral equation mei applied to three-dimensional arbitrary surfaces. "Electronics Letters", Novembre 1997, vol. 33, núm. 24, p. 2029-2031.