To cite lsmeans in publications use:

Russell V. Lenth (2016). Least-Squares Means: The R Package lsmeans. Journal of Statistical Software, 69(1), 1-33.<doi:10.18637/jss.v069.i01>

Corresponding BibTeX entry:

  @Article{,
    title = {Least-Squares Means: The {R} Package {lsmeans}},
    author = {Russell V. Lenth},
    journal = {Journal of Statistical Software},
    year = {2016},
    volume = {69},
    number = {1},
    pages = {1--33},
    doi = {10.18637/jss.v069.i01},
  }