@article{ragusa_bosquetti_2007,  title={Analogue of the theorem of Birkhoff in a metric nonsymmetric theory of the gravitational-electromagnetic field},  volume={37},  ISSN={0103-9733},  url={https://doi.org/10.1590/S0103-97332007000300015},  DOI={10.1590/S0103-97332007000300015},  number={2a},  journal={Brazilian Journal of Physics},  publisher={Sociedade Brasileira de Física},  author={Ragusa, S. and Bosquetti, D.},  year={2007},  month={Jun},  pages={435–439} }