Came across this article:
Maximinus and the Thracians. Herodian on the Coup of 235, and Ethnic Networks in the Roman Army
https://www.academia.edu/28458909/Maximinus_and_the_Thracians._Herodian_on_the_Coup_of_235_and_Ethnic_Networks_in_the_Roman_Army_of_the_Third_Century_CE
Thought people might be interested.
David