To cite package FORTLS in publications use:

Molina-Valero JA, Ginzo Villamayor MJ, Novo Pérez AM, Martínez-Calvo A, Álvarez-González JG, Montes F, Pérez-Cruzado C (2021). FORTLS: Automatic processing of TLS point cloud data for forestry purposes. R package version 1.0.6, https://CRAN.R-project.org/package=FORTLS.

Corresponding BibTeX entry:

  @Manual{,
    title = {{FORTLS}: Automatic processing of TLS point cloud data for
      forestry purposes},
    author = {Juan Alberto Molina-Valero and María José {Ginzo
      Villamayor} and Antonio Manuel {Novo Pérez} and Adela
      Martínez-Calvo and Juan Gabriel Álvarez-González and Fernando
      Montes and César Pérez-Cruzado},
    year = {2021},
    note = {R package version 1.0.6},
    url = {https://CRAN.R-project.org/package=FORTLS},
  }