To cite the MetCirc package in publications use:

  Thomas Naake and Emmanuel Gaquerel. MetCirc: navigating mass spectral
  similarity in high-resolution MS/MS metabolomics data. Bioinformatics
  33, 2419-2420 (2017).

A BibTeX entry for LaTeX users is

  @Article{,
    title = {MetCirc: navigating mass spectral similarity in high-resolution MS/MS metabolomics data},
    author = {Thomas Naake and Emmanuel Gaquerel},
    journal = {Bioinformatics},
    year = {2017},
    volume = {33},
    pages = {2419-2420},
  }