To cite fmcmc in publications use:

Vega Yon et al., (2019). fmcmc: A friendly MCMC framework. Journal of Open Source Software, 4(39), 1427, https://doi.org/10.21105/joss.01427

And the actual R package:

Vega Yon G, Marjoram P (2025). fmcmc: A friendly MCMC framework. doi:10.32614/CRAN.package.fmcmc. R package version 0.6-0, https://cran.r-project.org/package=fmcmc.

Corresponding BibTeX entries:

  @Article{,
    entry = {Article},
    title = {fmcmc: A friendly MCMC framework},
    author = {George {Vega Yon} and Paul Marjoram},
    journal = {The Journal of Open Source Software},
    year = {2019},
    month = {jul},
    volume = {4},
    number = {39},
    doi = {10.21105/joss.01427},
    url = {https://doi.org/10.21105/joss.01427},
  }

  @Manual{,
    title = {{{fmcmc: A friendly MCMC framework}}},
    author = {George {Vega Yon} and Paul Marjoram},
    year = {2025},
    note = {R package version 0.6-0},
    url = {https://cran.r-project.org/package=fmcmc},
    doi = {10.32614/CRAN.package.fmcmc},
  }