Thomas Aquinas--Legal Naturalism

Austin: Legal Positivism

Kelsen: Law as Normative Order

Alf Ross: Legal Norms and Observational Evidence

Jerome Frank: Legal Realism

L. Chipman Gray: A Realist Conception of Law

Hart: Positivism and the Separation of Law and Morals

Ronald Dworkin: The Model of Rules

Ronald Dworkin: Hard Cases

C.L.Ten: The Soundest Theory of Law

Jules Coleman: Negative and Positive Positivism