To cite package ‘sommer’ in publications use:

  Giovanny C (2016). “Genome assisted prediction of quantitative traits
  using the R package sommer.” _PLoS ONE_, *11*, 1-15.

A BibTeX entry for LaTeX users is

  @Article{,
    title = {Genome assisted prediction of quantitative traits using the R package sommer},
    author = {Covarrubias-Pazaran Giovanny},
    journal = {PLoS ONE},
    year = {2016},
    volume = {11},
    pages = {1-15},
  }