Negative Utilitarianism, by Dan Geinster: A manifesto defending this variety of utilitarianism. Defends a multidimensional approach to measure magnitude of pain.
Negative utilitarianism, by David Pearce: Challenges the moral symmetry of pleasure and pain. Most philosophers jump to the conclusion that it would justify erasing the world were that the only way to eradicate suffering - however it is a little more complicated than that.
Negativity: Short essay - some critical thoughts on negative utilitarianism: proposing an understanding of "negative" as a matter of degree.