To cite package 'iWeigReg' in publications use:

Tan, Z. and Shu, H. (2013). iWeigReg: Improved methods for causal inference and missing data problems. R package version 1.0.

Corresponding BibTeX entry:

  @Manual{,
    title = {iWeigReg: Improved methods for causal inference and
      missing data problems},
    author = {Zhiqiang Tan and Heng Shu},
    year = {2013},
    note = {R package version 1.0},
  }