To cite mmeta in publications use:

  Sheng Luo, Yong Chen, Xiao Su, Haitao Chu (2014). mmeta: An R Package
  for Multivariate Meta-Analysis. Journal of Statistical Software,
  56(11), 1-26. URL https://www.jstatsoft.org/v56/i11/

A BibTeX entry for LaTeX users is

  @Article{,
    title = {{mmeta}: An {R} Package for Multivariate Meta-Analysis},
    author = {Sheng Luo and Yong Chen and Xiao Su and Haitao Chu},
    journal = {Journal of Statistical Software},
    year = {2014},
    volume = {56},
    number = {11},
    pages = {1--26},
    url = {https://www.jstatsoft.org/v56/i11/},
  }