To cite the sommer package in publications use:

Covarrubias-Pazaran G. 2016. Genome assisted prediction of quantitative traits using the R package sommer. PLoS ONE 11(6):1-15.

Corresponding BibTeX entry:

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