Online Danish grammar book
Danish: An Essential Grammar - it looks good (and thorough, at 225 pp): https://nauchidatski.files.wordpress.com/2013/02./danish-a.
Google "Danish an essential grammar" - the url was too long and got cut off or up or something.
Sorry about that - next time I'll try to remember to check the link, not just copy it from the address bar.
And check higher up the tree (https://nauchidatski.wordpress.com/) - that seems to work ok: you can get Russian-Danish grammars and phrase books. Since I wouldn't have checked if you hadn't mentioned the problem, I'm glad you did. Also look further down the page - there's a video of Danish tongue twisters. I guess they mean, even more twisted than usual.