1. RTT Forman .2000 .Estimate of the area affected ecologically by the road system of the United States .Conserv Biol,14:31 -35 .
2. RTT Forman, and LE Alexander .1998 .Roads and their major ecological effects .Ann Rev Ecol Syst,29:207 -31 .
3. RTT Forman, and RD Deblinger .2000 .The ecological road-effect zone of a Massachusetts (USA) suburban highway .Conserv Biol,14:36 -46 .
4. GE, Jr Heilman, JR Strittholt, NC Slosser, and DA Dellasala .2002 .Forest fragmentation of the conterminous United States: assessing forest intactness through road density and spatial characteristics .BioScience,52:411 -22 .
5. KH Riitters, JD Wickham, and RV O'Neill .2002 .Fragmentation of continental United States forests .Ecosystems,5:815 -22 .