Elias N. Houstis, Theodore S. Papatheodorou. Algorithm 543: FFT9, Fast Solution of Helmholtz-Type Partial Differential Equations [D3]. ACM Transactions on Mathematical Software, 5(4):490-493, 1979. [doi]
@article{HoustisP79a,
title = {Algorithm 543: FFT9, Fast Solution of Helmholtz-Type Partial Differential Equations [D3]},
author = {Elias N. Houstis and Theodore S. Papatheodorou},
year = {1979},
doi = {10.1145/355853.355865},
url = {http://doi.acm.org/10.1145/355853.355865},
researchr = {https://researchr.org/publication/HoustisP79a},
cites = {0},
citedby = {0},
journal = {ACM Transactions on Mathematical Software},
volume = {5},
number = {4},
pages = {490-493},
}