@ARTICLE{
author={Levi VA,Nedic DP},
year={2001},
title={Application of the optimal power flow model in power system education},
journal={IEEE TRANSACTIONS ON POWER SYSTEMS},
volume={16},
number={4},
pages={572-580},
document_type={Article},
} 

@ARTICLE{
author={Levi VA,Nahman Jovan M,Nedic DP},
year={2001},
title={Security modeling for power system reliability evaluation},
journal={IEEE TRANSACTIONS ON POWER SYSTEMS},
volume={16},
number={1},
pages={29-37},
document_type={Article},
}