Need translation Norway date cancel with german censor tape?

[peetah]

Here's the date EXACTLY as it is shown on the cover:

-6 5.40.13-16  I'm guessing 6 May 1940. If so, then what is 13-16 ?

a label attached across the bottom reads:

Gepruft Obercommando der Wehrmacht

The cover was examined by German Army High Command?

[malolo]

petal - 13-16 would be the same as 1-4pm.

[malolo]

peetah - auto correct and to be overridden 3 times! LOL

[peetah]

Thanks! 🙂

[msgtdavid]

Hi

Would you provide a scan image?

[peetah]

here's my try at posting a front and back scan.