| |
| | The Ultimate Oklahoma - American History Information Guide and Reference (Site not responding. Last check: 2007-11-03) |
 | | The Ultimate Oklahoma - American History Information Guide and Reference |
 | | These ecoregions are: Western high plains, Southwestern Tablelands, Central Great Plains, Tall Grass Praire, Cross Timbers, Caves and Praire, Ozark Highlands, Ozark Forest, Hardwood Forest, Ouachita Mountains, and Cypress Swamps and Forests. |
 | | Oklahoma, in common with five other Mid-West states (Nebraska, Kansas, North Dakota, South Dakota and Iowa), is feeling the brunt of falling populations. |
| www.historymania.com /american_history/Oklahoma (2607 words) |
|