Quantum Mechanics and the Identity of Indiscernibles
- Essay by Allan Randall, relating Leibinz's criterion to Everett's possible worlds semantics of quantum mechanics.
- http://www.elea.org/Indiscernibles/

Relative Identity
- The view that there are objects which are the same F yet not the same G; from the Stanford Encyclopedia by Harry Deutsch.
- http://plato.stanford.edu/entries/identity-relative/

The Identity of Indiscernibles
- Entry by Peter Forrest in the Stanford Encyclopaedia of Philosophy. The principle is due to Leibniz, and states two entities are identical if they share the same properties.
- http://plato.stanford.edu/entries/identity-indiscernible/

Do Sentences Have Identity?
- Article by Jean-Yves Béziau presented at the 20th World Congress of Philosophy.
- http://www.bu.edu/wcp/Papers/Logi/LogiBeza.htm

The Paradox of Identity
- Report by William Greenberg. Argues for a Hegelian account of identity.
- http://structuredindividuals.com/paradox/toc.html