For an example of this approach in a single county in the United States (Olmstead County, Minnesota; home of the Mayo Clinic), see Sauver et al. (2011).
ສໍາລັບຕົວຢ່າງຂອງວິທີການນີ້ໃນ county ດຽວໃນປະເທດສະຫະລັດອະເມລິກາ (Olmstead County, Minnesota, ເຮືອນຂອງ Mayo Clinic), ເບິ່ງ Sauver et al. (2011).