Stanford encyclopedia of philosophy: The Metaphysics Research Lab, Center for the Study of Language and Information, Stanford University. The Metaphysics Research Lab, Stanford Univ.

Stanford Encyclopedia of Philosophy: The Metaphysics Research Lab, Center for the Study of Language and Information, Stanford University. Stanford, Calif.: The Metaphysics Research Lab, Stanford Univ.

Stanford Encyclopedia of Philosophy: The Metaphysics Research Lab, Center for the Study of Language and Information, Stanford University. The Metaphysics Research Lab, Stanford Univ.