1. Optimum megawatt-frequency control of multi-area electric energy systems;Elgerd;IEEE Trans,1970
2. The megawatt-frequency control problem: new approach via optimal control theory;Fosha;IEEE Trans,1970
3. C.W. Ross, Discussion in [2], pp. 571–572
4. G. Quazza, Discussion in [2], p. 573
5. N. Cohn, Discussion in [2], pp. 574–575