The sts package is released under the MIT license (see the file LICENSE).

Portions of the code are adapted from the stm package (Structural Topic
Models), version 1.3.8, by Margaret E. Roberts, Brandon M. Stewart and
Dustin Tingley (https://github.com/bstewart/stm). This includes the spectral
(anchor word) initialization, the STM variational EM routines used for
initialization = "stm" (R/stmPort.R and src/stmfuns.cpp), the functions
textProcessor(), prepDocuments() and make.heldout() (R/textProcessor.R), the
internal plotting helper plotQuote() (R/plotRepresentativeDocs.R), utilities in
R/helperFunctions.R, R/opt.mu.R and R/opt.sigma.R, and the gadarian data set.
That code is distributed under the following license:

  MIT License

  Copyright (c) 2017 Margaret Roberts, Brandon Stewart and Dustin Tingley

  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.

The gadarian data are from Gadarian, S. K. and Albertson, B. (2014),
"Anxiety, immigration, and the search for information," Political
Psychology 35(2): 133-164, as distributed with the stm package.
