To cite rSPDE in publications use the first of the following references to cite the package, the second to cite the covariance-based method (for instance if you used rSPDE in R-INLA or inlabru) and the third to cite the operator-based method:

Bolin D, Simas A (2022). rSPDE: Rational Approximations of Fractional Stochastic Partial Differential Equations. R package version 1.2.0, https://CRAN.R-project.org/package=rSPDE.

Xiong Z, Simas A, Bolin D (2022). “Covariance-based rational approximations of fractional SPDEs for computationally efficient Bayesian inference.” arXiv preprint arXiv:2209.04670. doi:10.48550/arXiv.2209.04670.

Bolin D, Kirchner K (2020). “The rational SPDE approach for Gaussian random fields with general smoothness.” Journal of Computational and Graphical Statistics, 29(2), 274–285. doi:10.1080/10618600.2019.1665537.

Corresponding BibTeX entries:

  @Manual{,
    title = {rSPDE: Rational Approximations of Fractional Stochastic
      Partial Differential Equations},
    author = {David Bolin and Alexandre B. Simas},
    year = {2022},
    note = {R package version 1.2.0},
    url = {https://CRAN.R-project.org/package=rSPDE},
  }

  @Article{,
    title = {Covariance-based rational approximations of fractional
      SPDEs for computationally efficient Bayesian inference},
    author = {Zhen Xiong and Alexandre B. Simas and David Bolin},
    journal = {arXiv preprint arXiv:2209.04670},
    year = {2022},
    doi = {10.48550/arXiv.2209.04670},
  }

  @Article{,
    title = {The rational {SPDE} approach for {Gaussian} random fields
      with general smoothness},
    author = {David Bolin and Kristin Kirchner},
    journal = {Journal of Computational and Graphical Statistics},
    year = {2020},
    volume = {29},
    number = {2},
    pages = {274--285},
    doi = {10.1080/10618600.2019.1665537},
  }