export(dfdt, evrunge, frunge, kmk, multirunge, nlscontour, nlsModel, plot.nlsrk, prepare, summary.nlsgrid, sys)
  importFrom("grDevices", "colors", "rainbow")
  importFrom("graphics", "abline", "axis", "contour", "filled.contour",
             "lines", "par", "plot", "points", "title")
  importFrom("stats", "fitted.values", "formula", "numericDeriv",
             "setNames")
  importFrom("utils", "stack")
  S3method(plot, nlsrk)
  S3method(summary, nlsgrid)
