When using pwt in publications, please cite both the pwt package and the Penn World Table itself:

To cite pwt, the R package, please use:

Achim Zeileis and Guan Yang (2009). pwt: Penn World Table. R package version 6.3-0. URL http://CRAN.R-project.org/package=pwt.

To cite the Penn World Table (version 6.3), please use:

Alan Heston, Robert Summers and Bettina Aten (2009). Penn World Table Version 6.3. Center for International Comparisons of Production, Income and Prices at the University of Pennsylvania URL http://pwt.econ.upenn.edu/.

Corresponding BibTeX entries:

  @Manual{,
    title = {pwt: Penn World Table},
    author = {Achim Zeileis and Guan Yang},
    year = {2009},
    note = {R package version 6.3-0},
    url = {http://CRAN.R-project.org/package=pwt},
  }

  @Manual{,
    title = {Penn World Table Version 6.3},
    author = {Alan Heston and Robert Summers and Bettina Aten},
    year = {2009},
    month = {August},
    organization = {Center for International Comparisons of Production,
      Income and Prices at the University of Pennsylvania},
    url = {http://pwt.econ.upenn.edu/},
  }