"Ever Since Darwin: Reflections in Natural History". Book by Stephen Jay Gould. "Why We Should Not Name Human Races - A Biological View", p. 231, 1977.
Viktor Schauberger, Callum Coats (2000). “The Energy Evolution – Harnessing Free Energy from Nature: Volume 4 of Renowned Environmentalist Viktor Schauberger’s Eco-Technology Series”, p.51, Gill & Macmillan Ltd
"Neil deGrasse Tyson and Executive Producer Ann Druyan Talk COSMOS: A SPACETIME ODYSSEY, Public Appetite for Science, and More". Interview with Christina Radish, collider.com. March 17, 2014.
"Neil deGrasse Tyson and Executive Producer Ann Druyan Talk COSMOS: A SPACETIME ODYSSEY, Public Appetite for Science, and More". Interview with Christina Radish, collider.com. March 17, 2014.