methods, survival, plyr, reshape, ggplot2, nleqslv
methods, reshape, plyr, nleqslv, ggplot2, grid
ggplot2, grDevices, grid, nleqslv, plyr, reshape, stats, utils
ggplot2, grDevices, grid, nleqslv, plyr, reshape, stats,
survival, utils
data.table (>= 1.9.8), ggplot2, grDevices, grid, nleqslv,
splines2, stats, survival