citHeader("To cite Formula in publications use")

## R >= 2.8.0 passes package metadata to citation().
if(!exists("meta") || is.null(meta)) meta <- packageDescription("Formula")
year <- sub("-.*", "", meta$Date)
note <- sprintf("R package version %s", meta$Version)

citEntry(entry = "Manual",
         title = "{Formula}: Extended Formulas",
         author = personList(as.person("Yves Croissant"), 
			     as.person("Achim Zeileis")),
         year = year,
         note = note,
         url = "http://CRAN.R-project.org/package=Formula",

         textVersion =
         paste("Yves Croissant, Achim Zeileis",
   	       sprintf("(%s).", year),	 
               "Formula: Extended Formulas.",
	       paste(note, ".", sep = ""),
               "URL http://CRAN.R-project.org/package=Formula")
)
