To cite package ‘fgsea’ in publications use:

  G. Korotkevich, V. Sukhov, A. Sergushichev. Fast gene set enrichment
  analysis. bioRxiv (2019), doi:10.1101/060012

A BibTeX entry for LaTeX users is

  @Article{,
    author = {Gennady Korotkevich and Vladimir Sukhov and Alexey Sergushichev},
    title = {Fast gene set enrichment analysis},
    year = {2019},
    doi = {10.1101/060012},
    publisher = {Cold Spring Harbor Labs Journals},
    url = {http://biorxiv.org/content/early/2016/06/20/060012},
    journal = {bioRxiv},
  }