Works Cited
"Field Trip Earth: Elephants as Keystone Species." Field Trip Earth: Elephants as Keystone Species. N.p., n.d. Web. 25 Mar. 2015.
"Invasive Plant Species in Oklahoma Grasslands: Ecology, Management and Restoration - OKLAHOMA STATE UNIVERSITY." Invasive Plant Species in Oklahoma Grasslands: Ecology, Management and Restoration - OKLAHOMA STATE UNIVERSITY. N.p., n.d. Web. 25 Mar. 2015.