To cite package ‘SIGN’ in publications use:

  Madani Tonekaboni S, Beri G, Ortmann J, Haibe-Kains B (2018). _SIGN:
  Similarity Identification in Gene Expression_. R package version
  0.1.0, <https://CRAN.R-project.org/package=SIGN>.

A BibTeX entry for LaTeX users is

  @Manual{,
    title = {SIGN: Similarity Identification in Gene Expression},
    author = {Seyed Ali {Madani Tonekaboni} and Gangesh Beri and Janosch Ortmann and Benjamin Haibe-Kains},
    year = {2018},
    note = {R package version 0.1.0},
    url = {https://CRAN.R-project.org/package=SIGN},
  }