The acousticTS package as a whole is distributed under GPL-3. The files
src/prolate_swf.f90, src/param.f90, and src/param_quad.f90 contain or adapt
code from the prolate_swf project:

  https://github.com/MathieuandSpheroidalWaveFunctions/prolate_swf

That upstream code was developed by Arnie Lee Van Buren and Jeffrey E.
Boisvert and is distributed under the following license. It has been
substantially modified for acousticTS by Brandyn Lucca. The upstream
authors did not participate directly in development of the R package;
their Authors@R entries identify the origin of the adapted code.

MIT License

Copyright (c) 2021 Arnie Lee Van Buren

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.