@INPROCEEDINGS {4083,
author={L.   Cancela and J. J. O.  Pires},
doi={},
booktitle={Conf. on Telecommunications  - ConfTele},
title={An Approach for Calculating the Performance of DPSK Direct Detection Systems with Semiconductor Optical Amplifiers},
year={2007},
month={May},
volume={-},
pages={---} 
}