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

if(!exists("meta") || is.null(meta)) meta <- packageDescription("pwt")
year <- sub("-.*", "", meta$Date)
note <- sprintf("R package version %s", meta$Version)

citEntry(entry = "Manual",
         title = "pwt: Penn World Table",
         author = personList(as.person("Achim Zeileis"),
			     as.person("Guan Yang")),
         year         = year,
         note         = note,
	 url          = "http://CRAN.R-project.org/package=pwt",

         textVersion = 
         paste("Achim Zeileis and Guan Yang",
               sprintf("(%s).", year),
               "pwt: Penn World Table.",
	       paste(note, ".", sep = ""),
	       "URL http://CRAN.R-project.org/package=pwt."),
	 header = "To cite pwt, the R package, please use:"
)

citEntry(entry = "Manual",
         title = "Penn World Table Version 7.1",
         author = personList(as.person("Alan Heston"),
	                     as.person("Robert Summers"), 
	                     as.person("Bettina Aten")),
         year         = "2012",
	 month        = "July",
	 organization = "Center for International Comparisons of Production, Income and Prices at the University of Pennsylvania",
         url          = "http://pwt.econ.upenn.edu/",
         
         textVersion = 
         paste("Alan Heston, Robert Summers and Bettina Aten (2012).", 
               "Penn World Table Version 7.1.",
               "Center for International Comparisons of Production, Income and Prices at the University of Pennsylvania",
               "URL http://pwt.econ.upenn.edu/."),
	 header = "To cite the Penn World Table (version 7.1), please use:"
)
