On Liberty by John Stuart Mill. One of the defining texts of the liberal tradition. It remains one of the clearest and richest articulations of liberal commitments. https://www.utilitarianism.com/ol/one.html

Key Documents of Liberty. Here can be found the text of many important legal documents and declarations that were part of the historical development of liberalism. http://oll.libertyfund.org/pages/key-documents

The Universal Declaration of Human Rights. Perhaps the most important modern articulation of individual rights. http://www.un.org/en/universal-declaration-human-rights/

‘Liberalism’ entry – Stanford Encyclopedia of Philosophy. Provides a clear overview and introduction to some of the most important philosophical debates within contemporary liberalism. https://plato.stanford.edu/entries/liberalism/

‘Justice course’ – Harvard University. Videos of lectures by the communitarian thinker Michael Sandel on a course he teaches at Harvard University. While the lectures are not focussed purely upon liberalism, many of the themes and thinkers covered within the chapter are covered within them in an informed and engaging style. http://justiceharvard.org/justicecourse/