R (>= 2.10), maptools, sp, foreign, methods, grDevices, base,
stats, utils, UScensus2000tract, UScensus2000cdp, gpclib
R (>= 2.10), maptools, sp, foreign, methods, grDevices, base,
stats, utils, UScensus2000tract, UScensus2000blkgrp,
UScensus2000cdp, gpclib