To cite quantspec in publications use:

Tobias Kley (2016). Quantile-Based Spectral Analysis in an Object-Oriented Framework and a Reference Implementation in R: The quantspec Package. Journal of Statistical Software, 70(3), 1-27.<doi:10.18637/jss.v070.i03>

Corresponding BibTeX entry:

  @Article{,
    title = {Quantile-Based Spectral Analysis in an Object-Oriented
      Framework and a Reference Implementation in {R}: The {quantspec}
      Package},
    author = {Tobias Kley},
    journal = {Journal of Statistical Software},
    year = {2016},
    volume = {70},
    number = {3},
    pages = {1--27},
    doi = {10.18637/jss.v070.i03},
  }