To cite sicegar in publications use

  Caglar MU, Teufel AI, Wilke CO. 2018. Sicegar: R package for
  sigmoidal and double-sigmoidal curve fitting. PeerJ 6:e4251
  https://doi.org/10.7717/peerj.4251

A BibTeX entry for LaTeX users is

  @Article{,
    title = {Sicegar: {R} package for sigmoidal and double-sigmoidal curve fitting},
    author = {M. Umut Caglar and Ashley I. Teufel and Claus O. Wilke},
    year = {2018},
    journal = {PeerJ},
    volume = {6},
    pages = {e4251},
    doi = {10.7717/peerj.4251},
  }