To cite quickpsy in publications use:

Linares, D., López-Moliner, J. (2016) quickpsy: An R Package to Fit Psychometric Functions for Multiple Groups. The R Journal, 8(1), 122-131.

Corresponding BibTeX entry:

  @Article{,
    title = {quickpsy: An R Package to Fit Psychometric Functions for
      Multiple Groups},
    author = {Daniel Linares and Joan López-Moliner},
    journal = {The R Journal},
    year = {2016},
    volume = {8},
    number = {1},
    pages = {122--131},
    url =
      {https://journal.r-project.org/archive/2016-1/linares-na.pdf},
  }