To cite package 'pan' in publications use:

Jing Hua Zhao, Joseph L. Schafer (2015). pan: Multiple imputation for multivariate panel or clustered dataR package version 1.3.

Corresponding BibTeX entry:

  @Manual{,
    title = {pan: Multiple imputation for multivariate panel or
      clustered data},
    author = {Jing Hua Zhao and Joseph L. Schafer},
    year = {2015},
    note = {R package version 1.3},
  }