Further discussions:
Ayn Rand, For the New Intellectual: The Philosophy of Ayn Rand (New York: Random House, 1961), pp. 3-67.

Ayn Rand, "The Objectivist Ethics," in The Virtue of Selfishness: A New Concept of Egoism (New York: The New American Library, 1964), pp. 16, 19-20, 21-22, 24.

Nathaniel Branden, "The Divine Right of Stagnation," in The Virtue of Selfishness: A New Concept of Egoism (New York: The New American Library, 1964), p. 165.

Nathaniel Branden, "The Psychology of Pleasure," in The Virtue of Selfishness: A New Concept of Egoism (New York: The New American Library, 1964), pp. 76-77.

Ayn Rand, "Playboy's Interview with Ayn Rand" (March 1964) [reprint pamphlet] (Oceanside, California: Second Renaissance Books), pp. 5-7.

Ayn Rand, "Patents and Copyrights," in Capitalism: The Unknown Ideal (New York: The New American Library, 1967), p. 130.

Nathaniel Branden, The Psychology of Self-Esteem: A New Concept of Man's Psychological Nature (New York: Bantam Books, 1969), pp. 127-132, 133-134, 196.

Ayn Rand, "Patents and Copyrights," in Capitalism: The Unknown Ideal (New York: Signet, 1967), p. 130.

Ayn Rand, "From My 'Future File'," Ayn Rand Letter v. 3 no. 26 (September 23, 1974), pp. 3-4.

Douglas J. Den Uyl and Douglas B. Rasmussen, "Life, Teleology, and Eudaimonia in the Ethics of Ayn Rand," in Douglas J. Den Uyl and Douglas B. Rasmussen, eds., The Philosophic Thought of Ayn Rand (Urbana, Illinois: University of Illinois Press, 1984), pp. 72-74.

J. Charles King, "Life and the Theory of Value: The Randian Argument Reconsidered," in Douglas J. Den Uyl and Douglas B. Rasmussen, eds., The Philosophic Thought of Ayn Rand (Urbana, Illinois: University of Illinois Press, 1984), pp. 117-119.

Eric Mack, "The Fundamental Moral Elements of Rand's Theory of Rights," in Douglas J. Den Uyl and Douglas B. Rasmussen, eds., The Philosophic Thought of Ayn Rand (Urbana, Illinois: University of Illinois Press, 1984), pp. 136-143, 149-150.

Paul St. F. Blair, "The Randian Argument Reconsidered: A Reply to Charles King," Reason Papers no. 10 (Spring 1985), pp. 97-99.

Leonard Peikoff, Objectivism: The Philosophy of Ayn Rand (New York: Dutton, 1991), pp. 292-303.

Michael S. Berliner, ed., Letters of Ayn Rand (New York: Penguin, 1995), pp. 82-83.

Chris Matthew Sciabarra, Ayn Rand: The Russian Radical (University Park, Pennsylvania: The Pennsylvania State University Press, 1995), pp. 246-248.

Tara Smith, Moral Rights and Political Freedom (Lanham, Maryland: Rowman & Littlefield Publishers, Inc., 1995), pp. 32-37, 50-51, 191.

David Harriman, ed., Journals of Ayn Rand (New York: Dutton, 1997), pp. 510, 549-551, 600-602, 616.

Robert Tracinski, The Heroism of Productive Work: An Intellectual History (Irvine, California: Ayn Rand Bookstore, 1999), [audio].

Donna Greiner and Theodore B. Kinni, Ayn Rand and Business (New York: Texere, 2001), pp. 114-124.

Tara Smith, The Value of Purpose (Irvine, California: Ayn Rand Bookstore, 2002), [audio].

Tara Smith, "The Value of a Central Productive Purpose," (unpublished).

Tara Smith, Ayn Rand's Normative Ethics: The Virtuous Egoist (Cambridge: Cambridge University Press, 2006), pp. 198-220.