2Thomas Aquinas, Summa Theologica, Part Ⅱ. ii. 57.1-4.
3Brian Tierney, The Idea of Natural Rights: Studies on Natural RightS, Natural Law and Church Law 1150-1625, Atlanta, Georgia.. Scholars Press, 1997, pp. 58,210.
4Brian Tierney, The Idea of Natural Rights: Studieson Natural Rights, Natural Law and Church Law 1150-1625, Atlanta, Georgia: Scholars Press, 1997, pp. 316,327,303.
5John Finnis, Natural Law and Natural Right, Oxford: Clarendon Press, pp. 205-210.
6Henry de Bracton, On the laws and Customs of England, Cambridge: the Belknap Press of Harvard University Press, 1968, p. 23.