exportPattern("^[[:alpha:]]+")

importFrom("grDevices", "col2rgb", "rgb")
  importFrom("graphics", "grid", "lines", "plot", "points", "polygon",
             "text")
  importFrom("stats", "median", "model.frame", "model.matrix", "pnorm",
             "rnorm", "dnorm", "runif", "uniroot")
  importFrom("utils", "combn")
