Dyson, Freeman. 1979. “Time Without End: Physics and Biology in an Open Universe.” Reviews of Modern Physics 51 (3), July. http://bit.ly/2rqneTo.
461
Pollack, James, and Carl Sagan. 1993. “Planetary Engineering.” In Resources of Near Earth Space. Lewis, J., M. Matthews, and M. Guerreri (eds.). Tucson: University of Arizona Press; Niven, Larry. 1990. Ringworld. New York: Ballantine; Stapledon, Olaf. 1968. The Starmaker. New York: Dover.
