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
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
Mike Michalowicz (2008). “The Toilet Paper Entrepreneur: The Tell-it-like-it-is Guide to Cleaning Up in Business, Even If You are at the End of Your Roll”, p.126, Toilet Paper Entrepreneur