▁End ▁of ▁the ▁Batt les ▁of ▁the ▁Som me , ▁London : ▁Mac mill an , ▁ 1 9 3 8 / Im per ial ▁War ▁Museum ▁& ▁B atter y ▁Press , ▁ 1 9 9 2 , ▁. ▁ ▁Gen ▁Sir ▁Frederick ▁P ile ' s ▁des patch : ▁' The ▁Anti - A ircraft ▁Def ence ▁of ▁the ▁United ▁Kingdom ▁from ▁ 2 8 th ▁July , ▁ 1 9 3 9 , ▁to ▁ 1 5 th ▁April , ▁ 1 9 4 5 ' ▁London ▁Gazette ▁ 1 8 ▁December ▁ 1 9 4 7 ▁ ▁Brig ▁N . W . ▁Rout ledge , ▁History ▁of ▁the ▁Royal ▁Regiment ▁of ▁Art illery : ▁Anti - A ircraft ▁Art illery ▁ 1 9 1 4 – 5 5 , ▁London : ▁Royal ▁Art illery ▁Institution / B ras sey ' s , ▁ 1 9 9 4 , ▁. ▁ ▁Edward ▁M . ▁S pi ers , ▁The ▁Army ▁and ▁Society ▁ 1 8 1 5 – 1 9 1 4 , ▁London : ▁Long mans , ▁ 1 9 8 0 , ▁. ▁ ▁Ray ▁West la ke , ▁T rac ing ▁the ▁R if le ▁Vol unte ers , ▁Bar ns ley : ▁Pen ▁and ▁S word , ▁ 2 0 1 0 , ▁. ▁ ▁Online ▁sources ▁ ▁The ▁Dr ill ▁Hall ▁Project ▁ ▁Great ▁War ▁Cent en ary ▁Dr ill ▁H alls ▁ ▁The ▁Long , ▁Long ▁Tra il ▁ ▁Land ▁Forces ▁of ▁Britain ,