The problem with scientific papers is that I could provide you one, or even more but I am not (yet) in the psoition to judge which paper is reliable. There are too many parties involed and it depends upon the financee of the paper. Therefore I provided the link to akc which depends on scientific and general believes. They have no direct incentive in one or the other stance. One of their goals is to take care of dogs. If it was questionable, they should reflect it in their stance. They do not reflect it, hence there is not enough evidence against it, as long as you take proper care of the dog.
One paper supporting a vegan diet
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0265662
But:
This research and its publication open access was funded by food awareness organisation ProVeg International
That’s alright. Right now, I’m curious enough about the nutritional needs of the dog and how a vegan diet for dogs work