1. Stapledon, 292.
2. Dick, editor, Many Worlds, 205. George Basalla addressed this linkage at length in his book Civilized Life in the Universe, published by Oxford University Press in 2006. Unfortunately, I did not see this book until after I sent my manuscript to my publisher.
3. Guthke, ix; Sagan, editor, CETI, 344–345.
4. Gerritt L. Verschuur, “If We Are Alone, What on Earth Are We Doing?” Sky and Telescope, November 1989, 452.
5. Swift, 57; S.A. Kaplan, editor, Extraterrestrial Civilizations, 215.