To cite LDheatmap in publications use:

Shin J-H, Blay S, McNeney B and Graham J (2006). LDheatmap: An R Function for Graphical Display of Pairwise Linkage Disequilibria Between Single Nucleotide Polymorphisms. J Stat Soft, 16 Code Snippet 3

Corresponding BibTeX entry:

  @Article{,
    title = {LDheatmap: An R Function for Graphical Display of Pairwise
      Linkage Disequilibria Between Single Nucleotide Polymorphisms.},
    author = {J.-H. Shin and S. Blay and B. McNeney and J. Graham},
    journal = {J Stat Soft},
    volume = {16},
    year = {2006},
    pages = {{Code Snippet 3}},
    url = {http://stat.sfu.ca/statgen/research/ldheatmap.html},
  }