France and Belgium 1:50,000, Ardres
This topographic sheet has information on defenses in the area overprinted in green, indicating searchlight positions, gun emplacements, and other data. France and Belgium 1:50 000 , Series GSGS 4040 [Defences].
The British LibraryGreat Britain. Army. Royal Engineers. Map Reproduction Section, 18th.
1943
[S.l.] : [s.n.]