Fletcher, R., and M. J. D. Powell. “A Rapidly Convergent Descent Method for Minimization”. The Computer Journal, vol. 6, no. 2, 1963, pp. 163-8, https://doi.org/10.1093/comjnl/6.2.163.
Fletcher, R., & Powell, M. J. D. (1963). A Rapidly Convergent Descent Method for Minimization. The Computer Journal, 6(2), 163-168. https://doi.org/10.1093/comjnl/6.2.163
Fletcher R, Powell MJD. A Rapidly Convergent Descent Method for Minimization. The Computer Journal. 1963;6(2):163-8.