If you use varSelRF please cite Diaz-Uriarte, 2007 at a minimum. If you refer to the variable selection procedure, you also want to cite Diaz-Uriarte and Alvarez de Andres, 2006.

R Diaz-Uriarte. GeneSrF and varSelRF: a web-based tool and R package for gene selection and classification using random forest 2007. BMC Bioinformatics, 8, https://bmcbioinformatics.biomedcentral.com/articles/10.1186/1471-2105-8-328.

R Diaz-Uriarte and A Alvarez de Andres. Gene selection and classification of microarray data using random forest. 2006. BMC Bioinformatics, 7, https://bmcbioinformatics.biomedcentral.com/articles/10.1186/1471-2105-7-3.

Corresponding BibTeX entries:

  @Article{,
    author = {R Diaz-Uriarte},
    title = {GeneSrF and varSelRF: a web-based tool and R package for
      gene selection and classification using random forest},
    journal = {BMC Bioinformatics},
    year = {2007},
    doi = {10.1186/1471-2105-8-328},
    url = {
      https://bmcbioinformatics.biomedcentral.com/articles/10.1186/1471-2105-8-328},
    volume = {8},
  }

  @Article{,
    author = {R Diaz-Uriarte and A Alvarez {de Andres}},
    title = {Gene selection and classification of microarray data using
      random forest.},
    journal = {BMC Bioinformatics},
    year = {2006},
    doi = {10.1186/1471-2105-7-3},
    url =
      {https://bmcbioinformatics.biomedcentral.com/articles/10.1186/1471-2105-7-3},
    volume = {7},
  }