To cite package ‘lattice’ in publications use:

  Sarkar D (2008). _Lattice: Multivariate Data Visualization with R_.
  Springer, New York. ISBN 978-0-387-75968-5.
  <http://lmdvr.r-forge.r-project.org>.

A BibTeX entry for LaTeX users is

  @Book{,
    title = {Lattice: Multivariate Data Visualization with R},
    author = {Deepayan Sarkar},
    year = {2008},
    publisher = {Springer},
    address = {New York},
    isbn = {978-0-387-75968-5},
    url = {http://lmdvr.r-forge.r-project.org},
  }