The font ''Mittelschrift'' doesn't exist anymore. On the bottom of the site there is a download button for a .CDR file, how can I open this file?
It's a corel draw file. You should be able to open it through this site which will convert it to pdf files:
https://www.zamzar.com/convert/cdr-to-pdf/
And here is a list of files that can open those files:
https://extension.nirsoft.net/cdr
Cheers,
priller