To cite the MetNet package in publications use:

  Thomas Naake and Alisdair R. Fernie. MetNet: Metabolite Network
  Prediction from High-Resolution Mass Spectrometry Data in R Aiding
  Metabolite Annotation. Analytical Chemistry 91, 1768-1772 (2019).

A BibTeX entry for LaTeX users is

  @Article{,
    title = {MetNet: Metabolite Network Prediction from High-Resolution Mass Spectrometry Data in R Aiding Metabolite Annotation},
    author = {Thomas Naake and Alisdair R. Fernie},
    journal = {Analytical Chemistry},
    year = {2019},
    volume = {91},
    pages = {1768-1772},
  }