To cite multiGSEA in publications use:

  Canzler, Sebastian and Hackermüller, Jörg: multiGSEA: A GSEA-based
  pathway enrichment analysis for multi-omics data. BMC Bioinformatics
  21, 561 (2020). https://doi.org/10.1186/s12859-020-03910-x

A BibTeX entry for LaTeX users is

  @Article{,
    title = {{multiGSEA}: {A GSEA}-based pathway enrichment analysis for multi-omics data},
    author = {Canzler Sebastian and Jörg Hackermüller},
    year = {2020},
    journal = {BMC Bioinformatics},
    doi = {https://doi.org/10.1186/s12859-020-03910-x},
    volume = {21},
    organization = {Helmholtz-Centre for Environmental Research - UFZ},
  }