Additional resources for prayer:
The Circle Maker by Mark Batterson
Prayer by Richard Foster
Listening Prayer by Mary Geegh
Experiencing God through Prayer by Madame Jeanne Guyon
Prayer by O. Hallesby
Release the Power of Prayer by George Muller
With Christ in the School of Prayer by Andrew Murray
How to Pray by John Wesley
The Prayer of Jabez by Bruce Wilkinson
Hearing God by Dallas Willard
Prayer: Does It Make Any Difference? by Phillip Yancey