Khan, I., M. Mallick, M. Rafi, and F. Ullah. “An Efficient Margin and Sensitivity Analysis Based Method For Calculating Voltage Collapse”. SAMRIDDHI : A Journal of Physical Sciences, Engineering and Technology, Vol. 4, no. 01, June 2013, pp. 01-08, doi:10.18090/samriddhi.v4i1.1540.