NAGRATH IJ & KOTHARI D P, . (1989). MODERN POWERSYSTEM ANALYSIS. : TATA MC GRAW HILL.
NAGRATH IJ & KOTHARI D P, . 1989. MODERN POWERSYSTEM ANALYSIS. : TATA MC GRAW HILL.
NAGRATH IJ & KOTHARI D P, . MODERN POWERSYSTEM ANALYSIS. : TATA MC GRAW HILL. 1989.