To cite package ‘tictactoe’ in publications use:

Mori K (2018). tictactoe: Tic-Tac-Toe Game. R package version 0.2.3, https://github.com/kota7/tictactoe.

Corresponding BibTeX entry:

  @Manual{,
    title = {tictactoe: Tic-Tac-Toe Game},
    author = {Kota Mori},
    year = {2018},
    note = {R package version 0.2.3},
    url = {https://github.com/kota7/tictactoe},
  }