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
John Ortberg (2010). “God Is Closer Than You Think: This Can Be the Greatest Moment of Your Life Because This Moment Is the Place Where You Can Meet God”, p.105, ReadHowYouWant.com