To cite package ‘limma’ in publications use:

  Ritchie, M.E., Phipson, B., Wu, D., Hu, Y., Law, C.W., Shi, W., and
  Smyth, G.K. (2015). limma powers differential expression analyses for
  RNA-sequencing and microarray studies. Nucleic Acids Research 43(7),
  e47.

A BibTeX entry for LaTeX users is

  @Article{,
    author = {Matthew E Ritchie and Belinda Phipson and Di Wu and Yifang Hu and Charity W Law and Wei Shi and Gordon K Smyth},
    title = {{limma} powers differential expression analyses for {RNA}-sequencing and microarray studies},
    journal = {Nucleic Acids Research},
    year = {2015},
    volume = {43},
    number = {7},
    pages = {e47},
    doi = {10.1093/nar/gkv007},
  }