I am writing an excursus on contemporary naturalism for my thesis. In fact, after a brief introduction to the subject of moral philosophy and to ethical naturalism, I will analyze the Duke manifesto "Naturalizing ethics" and try to give an account of the implicit metaethics and normative ethics one may infer from the statements in the manifesto.
With respect to the excursus on contemporary naturalism, I am considering your classification in Michigan, Rutgers and Pittsburgh naturalism, and "bald naturalism".
While I can easily identify the authors supporting the latter two forms of naturalism (McDowell for Pittsburgh and Mackie for bald naturalism), I am facing difficulties tracking back the representatives of Michigan and Rutgers ethical naturalism. Hence, I hope that you are willing to help me by providing the relevant references, and (of course) to correct me if am wrong about the other two forms of ethical naturalism.