Duncan, thank you for the suggestion. This should be a plain text message, perhaps it will post correctly to the R-help Archives.
-- TMK -- 212-460-5430 home 917-656-5351 cell ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.