Ogunrinde, R. B., & Olaosebikan, T. E. (2016). Combination of Penalty Function, Lagrange Multiplier and Conjugate Gradient Methods for the Solution of Constrained Optimization Problems. Asian Bulletin of Energy Economics and Technology, 3(1), 1–8. https://doi.org/10.20448/journal.507/2016.3.1/507.1.1.8