Left-libertarianism is a term that has been used to describe several different libertarian political movements and theorists. Left-libertarianism, as defended by contemporary theorists such as Peter Vallentyne, Hillel Steiner and Michael Otsuka, is a doctrine that has a strong commitment to personal liberty and has an egalitarian view concerning natural resources, believing that it is illegitimate for anyone to claim private ownership of resources to the detriment of others. Some left-libertarians of this type support some form of income redistribution on the grounds of a claim by each individual to be entitled to an equal share of natural resources. Social anarchists, including Murray Bookchi, anarcho-communists such as Peter Kropotkin and anarcho-collectivists such as Mikhail Bakunin, are sometimes called left-libertarian. Noam Chomsky also refers to himself as a left libertarian.