References Information "Cheyenne River." Encyclopædia Britannica. Encyclopædia Britannica Online. Encyclopædia Britannica Inc., 2012. Web. 07 Mar. 2012. <http://www.britannica.com/EBchecked/topic/109955/Cheyenne-River>. Picture http://www.google.com/imgres?hl=en&sa=X&biw=1280&bih=827&tbm=isch&prmd=imvns&tbnid=k1FoORTkZoaICM:&imgrefurl=http://geology.com/state-map/south-dakota.shtml&docid=4tV3fhuUt6s4lM&imgurl=http://geology.com/state-map/maps/south-dakota-rivers-