- American Society for the Prevention of Cruelty to Animals17
- Royal Society for the Prevention of Cruelty to Animals10
- Animal Defence and Anti-Vivisection Society4
- Animal Welfare Institute4
- Regan, Tom4
- American Humane Association3
- United States. Department of Agriculture3
- American Council for Judaism2
- Gandhi, Mahatma, 1869-19482
- Singer, Peter, 1946-2
- Stevens, Christine2
- American Medical Association1
- Aristotle1
- Bergh, Henry, 1811-18881
- Culture and Animals Foundation1
- Descartes, Rene, 1596-16501
- Humane Slaughter Association1
- Kant, Immanuel, 1724-18041
- Moore, G. E. (George Edward), 1873-19581
- Narveson, Jan, 1936-1