De la Grasserie, Les principes sociologiques du droit civil, ch. 6.

Duguit, in Progress of the Law in the Nineteenth Century (Continental Legal History Series, Vol. XI), 100-124.

Kant, Metaphysische Anfangsgründe der Rechtslehre (2 ed.), §§ 18-21.

Hegel, Grundlinien der Philosophie des Rechts, §§ 71-81.

Richte, Grundlage des Naturrechts, §§ 18-20.

Williston, Contracts, I, §§ 99-204.

Ames, The History of Assumpsit, 2 Harvard Law Review, 1, 53.

----, Two Theories of Consideration, 12 Harvard Law Review, 515; 13 Harvard Law Review, 29.

Beale, Notes on Consideration, 17 Harvard Law Review, 71.

Langdell, Mutual Promises as a Consideration for Each Other, 14 Harvard Law Review, 496.