Contemporary left-libertarian scholars such as David Ellerman, Michael Otsuka, Hillel Steiner, Peter Vallentyne and Philippe Van Parijs root an economic egalitarianism in the classical liberal concepts of self-ownership and land appropriation, combined with geoist or physiocratic views regarding the ownership of land and natural resources (e.g. those of Henry George and John Locke). Neo-classical liberalism, also referred to as Arizona School liberalism or bleeding-heart libertarianism, focuses on the compatibility of support for civil liberties and free markets on the one hand and a concern for social justice and the well-being of the worst-off on the other.