Fletcher, R. “Function Minimization by Conjugate Gradients”. The Computer Journal, vol. 7, no. 2, 1964, pp. 149-54, https://doi.org/10.1093/comjnl/7.2.149.
Fletcher, R. (1964). Function minimization by conjugate gradients. The Computer Journal, 7(2), 149-154. https://doi.org/10.1093/comjnl/7.2.149
Fletcher R. Function minimization by conjugate gradients. The Computer Journal. 1964;7(2):149-54.