"Despite Global Warming, Scientists Say to Expect Another Ice Age—In 5,000 Years". George Kukla's remarks at the international symposium convened by the Lamont-Doherty Earth Observatory, www.columbia.edu. February 25, 2000.
Dr. Robert C. Worstell, Dorothea Brande, Claude M. Bristol, Earl Nightingale, Napoleon Hill (2017). “Mindset StackingTM Inspirational Journal VolumeSS01”, p.164, Lulu.com