A lot of people confuse 'Scandinavian' with 'Nordic'. Scandinavia is a geographical description, Nordic is more cultural, which includes Scandinavia, Finland and Iceland.
I was actually considering including Estonia in my list, but they are not a member of the Nordic Council. And Estonia's Nordic bona fide is a matter of dispute. Personally, I believe Estonia to be a Nordic country, including having the Nordic Cross design variant of the Estonian flag hanging on my wall.
Furthermore, in an article about military history, Scandinavia is understood - in a military geopolitical context - to only include Denmark, Norway and Sweden.
‣ https://satwcomic.com/new-nordic
‣ https://satwcomic.com/greatest-authority
‣ https://satwcomic.com/imposter
‣ https://satwcomic.com/party-crasher