@ARTICLE {33423,
author={A.  Fallah and Y.  Kiasat and M. G. Silveirinha and N. Engheta},
doi={10.1103/PhysRevB.103.214303},
journal={Physical Review B},
title={Nonreciprocal guided waves in the presence of swift electron beams},
year={2021},
month={June},
volume={103},
number={21},
pages={1-8},
ISSN={2469-9950}
}