William W. Hager, Hongchao Zhang. Algorithm 851: CG_DESCENT, a conjugate gradient method with guaranteed descent. ACM Transactions on Mathematical Software, 32(1):113-137, 2006. [doi]
@article{HagerZ06,
title = {Algorithm 851: CG_DESCENT, a conjugate gradient method with guaranteed descent},
author = {William W. Hager and Hongchao Zhang},
year = {2006},
doi = {10.1145/1132973.1132979},
url = {http://doi.acm.org/10.1145/1132973.1132979},
researchr = {https://researchr.org/publication/HagerZ06},
cites = {0},
citedby = {0},
journal = {ACM Transactions on Mathematical Software},
volume = {32},
number = {1},
pages = {113-137},
}