Shepherding Your Heart Through Ministry Fatigue, by Paul Shirley, The Expositors Seminary
Replenish by Lance Witt speaks directly to those in pastor/elder ministry who have been hurt and burned out from ministering to others.
How to Beat Burnout by Minirth, Hawkins, Meir and Flournoy, has also been helpful not only for pastors/elders but for any in the Christian church.
Spiritual Depression: Its Causes and Cures by D. Marytn Lloyd Jones is a must-read on depression that often occurs during times of burnout.
Disciplines of a Godly Man by Kent Hughes advocates for various disciplines in the Christian life, as well as pastor/elder life, that can keep us away from burnout.