To cite spsur in publications use:

Mínguez R, López FA, Mur J (2022). “spsur: An R Package for Dealing with Spatial Seemingly Unrelated Regression Models.” Journal of Statistical Software, 104(11), 1–43. doi:10.18637/jss.v104.i11.

López FA, Mínguez R, Mur J (2020). “ML versus IV estimates of spatial SUR models: evidence from the case of Airbnb in Madrid urban area.” The Annals of Regional Science, 64(2), 313–347. doi:10.1007/s00168-019-00914-1.

Corresponding BibTeX entries:

  @Article{,
    title = {{spsur}: An {R} Package for Dealing with Spatial Seemingly
      Unrelated Regression Models},
    author = {Rom{\'a}n M{\'i}nguez and Fernando A. L{\'o}pez and
      Jes{\'u}s Mur},
    journal = {Journal of Statistical Software},
    year = {2022},
    volume = {104},
    number = {11},
    pages = {1--43},
    doi = {10.18637/jss.v104.i11},
  }

  @Article{,
    title = {{ML} versus {IV} estimates of spatial {SUR} models:
      evidence from the case of {A}irbnb in {M}adrid urban area},
    author = {Fernando A. L{\'o}pez and Rom{\'a}n M{\'i}nguez and
      Jes{\'u}s Mur},
    journal = {The Annals of Regional Science},
    year = {2020},
    volume = {64},
    number = {2},
    pages = {313--347},
    doi = {10.1007/s00168-019-00914-1},
  }