| Thiel | Richard P. | Relationship between road densities and wolf haibtat suitability in Wisconsin. | 1985 | The American Midland Naturalist 113 (2):404-407 |
From USDI 1988:
"Data on demise of wolf and increase in road densities compared between 1926 and 1960. Wolves failed to survive when road densities exceed 0.93 miles/sq mi."