@article{ljs16031,
 author={Nagendra, P. and Dey, S. H. and Paul, a. S.},
 year={2010},
 title={Optimal Power Flow Based Global Voltage Stability Analysis Using Network Equivalencing Technique: A Case Study of Widespread Sub-Grid},
 journal={Leonardo J. Sci.},
 volume={9},
 number={16},
 pages={31-46},
 url={http://ljs.academicdirect.org/A16/031_046.pdf}
}