jom, here's a representative link
https://apdt.com/pet-owners/choosing-a-trainer/dominance/
google "dog dominance and pack theory disproved research" for a shedload of research based articles. Its not even true in wolves, the research on which it was based observed a group of wolves that were strangers brought together and forced to live in a confined area. Saying that research based on that group is valid in real life is as flawed as saying that Big Brother, or any of the other similar reality based shows, mirrors real life.
If you are seriously interested, i will post a reading list.