1. ACC 2007/195, Norwich Bomb Map kept by the Civil Defence Air Raid Precautions section of Norwich City Engineer‘s Department .
2. AIR 13/17, Enemy Action over Barrage Areas: No. 33 Group, Reports on Enemy Action 33G/S/3082/39/Ops 8 November 1942.
3. AIR 13/42a, Norwich: Balloon Barrage, R.A.F. Station, Horsham St Faith and Operation ‘Crittall’ at Norwich 9th August 1942 FC/S.28565/Ops.3(c).
4. AIR 13/42b, Norwich: Balloon Barrage, Reconnaissances for New Barrages or Additions to Barrages. Deployment of No. 993 (Mobile) Squadron at Norwich.
5. AIR 27/2338a, Squadron Number: 993 Summary of Events: Y, Operations Record Book May 1942.