Life Extension Society
- Brennan, Michael, ed. (2014). The A-Z of Death and Dying: Social, Medical, and Cultural Aspects. ABC-CLIO. p. 117. ISBN 1785398903. "During the mid-20th century, several cryonics organizations were formed. The first was Evan Cooper's Life Extension Society in 1963."
- Scott, Gini (2017). The Science of Living Longer: Developments in Life Extension Technology. ABC-CLIO. pp. 45–46. ISBN 1440857156. "Still, Cooper helped generate interest in freezing by becoming the first activist for cryonics, even though that name was not used until 1965, and his efforts led to forming the first cryonics organization called the Life Extension Society (LES)."