To cite package 'pan' in publications use:

Jing Hua Zhao, Joseph L. Schafer (2013). pan: Multiple imputation for multivariate panel or clustered dataR package version 0.9.

Corresponding BibTeX entry:

  @Manual{,
    title = {pan: Multiple imputation for multivariate panel or
      clustered data},
    author = {Jing Hua Zhao and Joseph L. Schafer},
    year = {2013},
    note = {R package version 0.9},
  }