(Ingelesez)Young, Robert. (2021). Zalta, Edward N. ed. «Voluntary Euthanasia»The Stanford Encyclopedia of Philosophy (Metaphysics Research Lab, Stanford University) (Noiz kontsultatua: 2022-04-21).
(Ingelesez)Siegel, Andrew. (2018). Zalta, Edward N. ed. «Ethics of Stem Cell Research»The Stanford Encyclopedia of Philosophy (Metaphysics Research Lab, Stanford University) (Noiz kontsultatua: 2022-04-21).
utm.edu
iep.utm.edu
(Ingelesez)Environmental Ethics. Internet Encyclopedia of Philosophy (Noiz kontsultatua: 2022-04-21).