To cite WASP in publications use:

  Jiang, Z., Sharma, A., & Johnson, F. (2020). Refining Predictor
  Spectral Representation Using Wavelet Theory for Improved Natural
  System Modeling. Water Resources Research, 56(3), e2019WR026962.
  <doi:10.1029/2019WR026962>.

A BibTeX entry for LaTeX users is

  @Article{,
    title = {Refining Predictor Spectral Representation Using Wavelet Theory for Improved Natural System Modeling},
    author = {Ze Jiang and Ashish Sharma and Fiona Johnson},
    journal = {Water Resources Research},
    year = {2020},
    volume = {56},
    number = {3},
    pages = {e2019WR026962},
    doi = {10.1029/2019WR026962},
  }

  Jiang, Z., Rashid, M. M., Johnson, F., & Sharma, A. (2020). A
  wavelet-based tool to modulate variance in predictors: an application
  to predicting drought anomalies. Environmental Modelling & Software,
  135, 104907.  <doi:10.1016/j.envsoft.2020.104907>.

A BibTeX entry for LaTeX users is

  @Article{,
    title = {A wavelet-based tool to modulate variance in predictors: an application to predicting drought anomalies},
    author = {Ze Jiang and Md. Mamunur Rashid and Fiona Johnson and Ashish Sharma},
    journal = {Environmental Modelling & Software},
    year = {2020},
    volume = {135},
    pages = {104907},
    doi = {10.1016/j.envsoft.2020.104907},
  }

  Jiang, Z., Sharma, A., & Johnson, F. (2021). Variable transformations
  in the spectral domain – Implications for hydrologic forecasting.
  Journal of Hydrology, 603, 126816.
  <doi:10.1016/J.JHYDROL.2021.126816>.

A BibTeX entry for LaTeX users is

  @Article{,
    title = {Variable transformations in the spectral domain – Implications for hydrologic forecasting},
    author = {Ze Jiang and Ashish Sharma and Fiona Johnson},
    journal = {Journal of Hydrology},
    year = {2021},
    volume = {603},
    pages = {126816},
    doi = {10.1016/J.JHYDROL.2021.126816},
  }

Additional information: https://github.com/zejiang-unsw/WASP#readme