U.S. Geological Survey. National Hydrography Dataset high-resolution flowline data. The National MapArhivirano 2012-03-29 na Wayback Machine., accessed March 30, 2011
U.S. Geological Survey. National Hydrography Dataset high-resolution flowline data. The National MapArhivirano 2012-03-29 na Wayback Machine., accessed March 30, 2011