Murphy, Mark (2019), "The Natural Law Tradition in Ethics", i Zalta, Edward N. (red.), The Stanford Encyclopedia of Philosophy (Summer 2019 udgave), Metaphysics Research Lab, Stanford University, arkiveret fra originalen 2021-11-13, hentet 2020-10-19
Finnis, John (2020), "Natural Law Theories", i Zalta, Edward N. (red.), The Stanford Encyclopedia of Philosophy (Summer 2020 udgave), Metaphysics Research Lab, Stanford University, arkiveret fra originalen 2021-09-10, hentet 2020-10-19
Murphy, Mark (2019), "The Natural Law Tradition in Ethics", i Zalta, Edward N. (red.), The Stanford Encyclopedia of Philosophy (Summer 2019 udgave), Metaphysics Research Lab, Stanford University, arkiveret fra originalen 2021-11-13, hentet 2020-10-19
Finnis, John (2020), "Natural Law Theories", i Zalta, Edward N. (red.), The Stanford Encyclopedia of Philosophy (Summer 2020 udgave), Metaphysics Research Lab, Stanford University, arkiveret fra originalen 2021-09-10, hentet 2020-10-19