▁the ▁Union ▁Col lapse , ▁and ▁the ▁Def ense ▁of ▁H ors es ho e ▁R idge , ▁September ▁ 2 0 , ▁ 1 8 6 3 . ▁El ▁Dor ado ▁Hills , ▁CA : ▁S avas ▁Be atie , ▁ 2 0 1 5 . ▁. ▁ ▁Pow ell , ▁David ▁A . ▁The ▁Ch ick am aug a ▁Camp aign : ▁Bar ren ▁Vict ory : ▁The ▁Ret re at ▁into ▁Ch att ano oga , ▁the ▁Confeder ate ▁P urs uit , ▁and ▁the ▁After math ▁of ▁the ▁Battle , ▁September ▁ 2 1 ▁to ▁October ▁ 2 0 , ▁ 1 8 6 3 . ▁El ▁Dor ado ▁Hills , ▁CA : ▁S avas ▁Be atie , ▁ 2 0 1 6 . ▁. ▁ ▁Robert son , ▁William ▁Gl enn . ▁River ▁of ▁Death : ▁the ▁Ch ick am aug a ▁Camp aign . ▁Chap el ▁Hill : ▁University ▁of ▁North ▁Carolina ▁Press , ▁ 2 0 1 8 . ▁. ▁ ▁Spr u ill , ▁Matt . ▁Guide ▁to ▁the ▁Battle ▁of ▁Ch ick am aug a . ▁The ▁U . S . ▁Army ▁War ▁College ▁gu ides ▁to ▁Civil ▁War ▁batt les . ▁Lawrence : ▁University ▁Press ▁of ▁Kansas , ▁ 1 9 9 3 . ▁. ▁ ▁White , ▁William ▁Lee . ▁Bush wh ack ing ▁on ▁a ▁Grand ▁Sc ale : ▁The ▁Battle ▁of ▁Ch ick am aug a , ▁September ▁ 1 8 – 2 0 , ▁ 1 8 6 3