NAGRATH I J & D P KOTHARI, . (1990). MODERN POWER SYSTEM ANALYSIS. : TATA MC GRAW HILL.
NAGRATH I J & D P KOTHARI, . 1990. MODERN POWER SYSTEM ANALYSIS. : TATA MC GRAW HILL.
NAGRATH I J & D P KOTHARI, . MODERN POWER SYSTEM ANALYSIS. : TATA MC GRAW HILL. 1990.