John Ortberg, Stephen Sorenson, Amanda Sorenson (2003). “If You Want to Walk on Water, You've Got to Get Out of the Boat: A 6-session Journey on Learning to Trust God”, p.32, Zondervan
John Ortberg, Stephen Sorenson, Amanda Sorenson (2003). “If You Want to Walk on Water, You've Got to Get Out of the Boat: A 6-session Journey on Learning to Trust God”, p.195, Zondervan