Billy's September letters begin on 10th.
#34 (September 10th 1953) He

Billy's next letter.
#35 (September 13th 1953) He

Billy's next letter
#36 (September 15th 1953) He

Billy's next letter
#37 (September 18th 1953) He

Billy's next letter
#38 (September 22nd + 25th 1953) He

Billy's final massive missive
#39 (September 27th 1953) He