God, Naturalism, and the Foundations of Morality by Paul Copan
Ethics Needs God by Paul Copan
Grounding Human Rights: Naturalism's Failure and Biblical Theism's Success by Paul Copan
The above works by Paul Copan provide arguments for the rationality of Christian theism as the ground for moral realism. They also critique other attempted foundations that are derived from naturalism. There is also extensive interaction with the Euthyphro dilemma in these articles.
Be sure to see Paul Copan's website for a number of other essays on all sorts of ethical issues--including difficult texts in the Bible (i.e., slavery, the destruction of the Canaanites, etc.).
Hume's Guillotine and Evolutionary Ethics: Evaluating Attempts to Overcome the Naturalistic Fallacy by Brenton H. Cook *This piece looks at the views of Stuart Kauffman, Frans de Waal, Ayn Rand, various variants of evolutionary behaviorism.
Is There an Evolutionary Foundation for Human Morality? by John Hare
Can Moral Objectivism Do Without God? by Peter S. Williams *Williams presents a moral argument for God's existence. He interacts with the work of atheist ethicist Russ Shafer-Landau.
Can We Be Good Without God? by William Lane Craig
Navigating Sam Harris' "The Moral Landscape" by William Lane Craig
The Indispensability of Theological Meta-ethical Foundations for Morality by William Lane Craig
Why I Am Not a Moral Relativist by Francis Beckwith
This page has a number of links to items of relevance on this topic.
Here are my previous "God & Truth" presentations:
The Objectivity of God, Morality, and Evil: A Perspective from Jesus (God & Truth III)
Metaphysics and the Meaning of Life: How the Kingdom of God Changes Everything! (God & Truth IV)
This is the video for God & Truth IV: God and the Meaning of Life