Horta, Oscar. 2010. "What is speciesism?" Journal of Agricultural and Environmental Ethics 23 (3): 243-66, pp. 244-27. doi10.1007/s10806-009-9205-2
Horta, Oscar. 2013. "Animals, Moral Status of", in LaFollette, Hugh, International Encyclopedia of Ethics. Hoboken: Wiley, 292-302 doi10.1002/9781444367072.wbiee156
Horta, Oscar. 2018. "Moral considerability and the argument from relevance" Journal of Agricultural and Environmental Ethics 31 (3): 369-88, p. 370. doi10.1007/s10806-018-9730-y
Horta, Oscar. 2010. "Discrimination in Terms of Moral Exclusion". "Theoria: Swedish Journal of Philosophy" 76: 346-364 doi10.1111/j.1755-2567.2010.01080.x .