What do you mean you “don’t believe” it?
I can see saying that it’s not that serious, but what is there that’s not to believe?
I will not believe it until I have access to a Lexisnexis platform to search for the actual occurrences of each instance to see how many times the "so called reference" had appeared earlier without attribution of the actual source. There are only set number of ways to say "the sky is blue." If I write that and it was already written by someone else...... pfft.