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 (2023). rSPDE: Rational Approximations of Fractional Stochastic Partial Differential Equations. R package version 2.3.3, https://CRAN.R-project.org/package=rSPDE.

Bolin D, Simas A, Xiong Z (2024). “Covariance-based rational approximations of fractional SPDEs for computationally efficient Bayesian inference.” Journal of Computational and Graphical Statistics, 33(1), 64–74. doi:10.1080/10618600.2023.2231051.

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 = {2023},
    note = {R package version 2.3.3},
    url = {https://CRAN.R-project.org/package=rSPDE},
  }

  @Article{,
    title = {Covariance-based rational approximations of fractional
      SPDEs for computationally efficient Bayesian inference},
    author = {David Bolin and Alexandre B. Simas and Zhen Xiong},
    journal = {Journal of Computational and Graphical Statistics},
    year = {2024},
    volume = {33},
    number = {1},
    pages = {64--74},
    doi = {10.1080/10618600.2023.2231051},
  }

  @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},
  }