"Section 3.3 – Codes for Entities"(PDF). 2009 TIGER/Line Shapefiles Technical Documentation. United States Census Bureau. 2009. Archived(PDF) from the original on 2020-08-05. Retrieved 2010-08-03.
"Section 3.3 – Codes for Entities"(PDF). 2009 TIGER/Line Shapefiles Technical Documentation. United States Census Bureau. 2009. Archived(PDF) from the original on 2020-08-05. Retrieved 2010-08-03.