To cite the 'specs' package in publications use:

Smeekes S, Wijler E (2020). “An automated approach towards sparse single-equation cointegration modelling.” arXiv e-print 1809.08889, arXiv.

Corresponding BibTeX entry:

  @TechReport{,
    title = {An automated approach towards sparse single-equation
      cointegration modelling},
    author = {Stephan Smeekes and Etienne Wijler},
    year = {2020},
    institution = {arXiv},
    type = {arXiv e-print},
    number = {1809.08889},
  }