To cite biwavelet in publications use:

Gouhier TC, Grinsted A, Simko V (2021). R package biwavelet: Conduct Univariate and Bivariate Wavelet Analyses. (Version 0.20.21), https://github.com/tgouhier/biwavelet.

Corresponding BibTeX entry:

  @Manual{,
    title = {R package {biwavelet}: Conduct Univariate and Bivariate
      Wavelet Analyses},
    author = {Tarik C. Gouhier and Aslak Grinsted and Viliam Simko},
    year = {2021},
    note = {(Version 0.20.21)},
    url = {https://github.com/tgouhier/biwavelet},
  }