@techreport{Carstensen2013,
author = {Carstensen, B., Plummer, M., Laara, E., and Hills, M.},
title= {Epi: A package for statistical analysis in epidemiology. R package version 1.1.49},
year = {2013},
URL = {http://CRAN.R-project.org/package=Epi},
}