@article{Hill:1981:ASV,
author = {Hill, G. W.},
title = {Algorithm 571: Statistics for von {M}ises' and {F}isher's
distributions of directions: {$I_1(x)/I_0(x)$},
{$I_{1.5}(x)/I_{0.5}(x)$} and their inverses [S14]},
journal = {ACM Trans. Math. Software},
fjournal = {Association for Computing Machinery. Transactions on
Mathematical Software},
volume = {7},
year = {1981},
number = {2},
pages = {233–238},
note = {Single-precision Fortran, minimum accuracy 8S.},
issn = {0098-3500},
doi = {10.1145/355945.355953},
links = {\GAMSmodule{TOMS}{571}{8610}}}