R (>= 2.13.0), ggplot2 (>= 0.8.9), RColorBrewer, gridExtra,
MASS
RColorBrewer, plyr, gridExtra, reshape2, proto, grid
RColorBrewer, plyr, gridExtra (>= 0.9.1), reshape2, grid
gridExtra (>= 0.9.1), plyr, RColorBrewer, reshape2