If your DNS is hosted by TornevallNET and need to point out a specific amount of nameservers, this is the page you should look at.
DNS-Servers marked with is, as said, partially recursive. By means, chosen networks - mostly located in Sweden - are allowed to use them as they normally use servers like 22.214.171.124, 126.96.36.199, 188.8.131.52, etc.
If you feel the resolvers is failing in such cases for you, take a look at the permission list at https://auth.tornevall.net/dns-recursion.txt and/or contact firstname.lastname@example.org if you wish to update something.
There are more servers like below, that allows recursion but those are the publicly maintained list.
184.108.40.206, or the IPv6-filtered all-recursion DNS has been removed since Netflix "works" again.