@INPROCEEDINGS {1941,
author={L. M. Correia and A. Barbosa},
doi={},
booktitle={Appl. Computational Electromagnetics Society Conf. - ACES},
title={An approximate (symmetric) combined field integral equation for the analysis of scattering by conducting bodies in the ressonance region},
year={1991},
month={March},
volume={1},
pages={190-197} 
}