What Is the Gospel? by R.C. Sproul
Understanding the Gospel by R.C. Sproul
Meaning of the Gospel by R.C. Sproul
Evangelism According to Jesus: 2008 National Conference
The Doctrine of Justification and the New Perspectives on Paul Resource Collection
Dr. David Murray also gave a lecture on this at First RPC’s 2008 Practical Theology Conference. Good stuff. Names something like 20 messages that are not the Gospel. It is shameful, the things we substitute for the Christ’s substitution for sinners.