1. D. Kirschen, G. Strback, Fundamentals of Power System Economics (Wiley Ltd, Chichester, England, 2004)
2. H. Nosair, F. Bouffard, Flexibility envelopes for power system operational planning. IEEE Trans. Sustain. Energy 6(3), 800–809 (2015)
3. International Energy Agency, in Harnessing Variable Renewables: A Guide to the Balancing Challenge, OECD/IEA, Paris, France, Tech. Rep. 61-2011-17-1P1 (2011)
4. North American Electric Reliability Corporation, Accomodating High Levels of Variable Generation, NERC, Princeton, NJ, USA, Tech. Rep (2009)
5. J. Cochran, M. Miller, O. Zinaman, M. Milligan, D. Arent, B. Palmintier, Flexibility in 21st Century Power Systems. NREL (2018)