To cite VNM in publications use:

Hyun SW, Wong WK and Yang Y (2018). “VNM: An R Package for Finding Multiple-Objective Optimal Designs for the 4-Parameter Logistic Model.” Journal of Statistical Software, 83(5), pp. 1–19. doi: 10.18637/jss.v083.i05.

Corresponding BibTeX entry:

  @Article{,
    title = {{VNM}: An {R} Package for Finding Multiple-Objective
      Optimal Designs for the 4-Parameter Logistic Model},
    author = {Seung Won Hyun and Weng Kee Wong and Yarong Yang},
    journal = {Journal of Statistical Software},
    year = {2018},
    volume = {83},
    number = {5},
    pages = {1--19},
    doi = {10.18637/jss.v083.i05},
  }