Dr. Robert C. Worstell, Dorothea Brande, Claude M. Bristol, Earl Nightingale, Napoleon Hill (2017). “Mindset StackingTM Inspirational Journal VolumeSS01”, Lulu.com
Tony Robbins (2007). “Awaken the Giant Within: How to Take Immediate Control of Your Mental, Emotional, Physical and Financial”, p.303, Simon and Schuster