There is so much stuff on the internet which can easily confuse developers who are new to understanding problem domains. So I created this page as a jumping off point that I can point new devs too.
First read my article Anatomy Of A Product to get an idea of WHY understanding Problem Domains is an important skill to learn.
While not directly talking about problem domains, this presentation by Micheal Plod is adjacent to the topic.
How about stack exchange https://softwareengineering.stackexchange.com/questions/125926/what-is-problem-domain