Robert H. Schuller (1993). “Robert H Schuller: The Inspirational Writings : Tough Times Never Last, But Tough People Do/Tough Minded Faith for Tender Hearted People”, Bbs Publishing Corporation
John Owen (1842). “The Mortification of Sin in Believers: Containing the Necessity, Nature and Means of It; with a Resolution of Sundry Cases of Conscience Thereto Belonging”, p.9