I'm pretty sure that everything that I did not come up with myself is linked to in the body of the article. Vermeulen and van den Akker's "Notes on Metamodernism," MacDowell's "Notes on Quirky" and Eshelman's "Performatism." The nutshell explanations of tradition, modernism and postmodernism are expressed in my own terms, but I would say they correspond to what you would learn in any undergraduate class in the humanities or the wikipedia article. I did not draw them from any particular source though. Is there anything specific that you'd like to see sourced?