Here is an article about Hartmann published in a peer-reviewed journal.
https://uir.unisa.ac.za/handle/10500/26467
Sad to see that the name of the journal has "science" in it. The authors straightly defined the Bf 109 as superior to all other WW2 aircraft which is an indication that they had no idea about the evolution of technologies during the war. After the introduction, I decided not to read it the rest of the article, except the conclusion section, where the authors concluded to nothing new. Unfortunately, while revealing nothing new, they received their academic points in their institutions for publishing an article in a journal.