The links are OK on Safari, Chrome and FireFox but not on Internet Explorer
Probably an new issue from my Dropbox account.
Unfortunately there is nothing I can do about that... sorry.
An alternative to medium 3,7mm AA gun battery, a light 20mm gun battery :
K.St.N.1713 (fG) (1.6.1944)
Heeresflakbattrie 2 cm (11 Geschütze) (mot Z)(Selbsferlatte) freie Gleiderung