Puzzles of the Black Widowers (1990), pp. 74-75
General sources
Isaac Asimov: Quotes about life (page 2)
Isaac Asimov was American writer and professor of biochemistry at Boston University, known for his works of science fiction and popular science. Explore interesting quotes on life.“All life is nucleic acid; the rest is commentary”
"The Relativity of Wrong" (1988) - "Beginning with Bone" (May 1987)
General sources
Mother Earth News interview (1980)
"By the Numbers" (May 1973), in The Tragedy of the Moon (1973), p. 190
General sources
Mother Earth News interview (1980)
“Religion is more conservative than any other aspect of human life.”
The Near East (1968), p. 14
General sources
The Foundation series (1951–1993), Forward the Foundation (1993)
Source: Part 5 "Epilogue", Hari Seldon's last words
Source: The Foundation series (1951–1993), Second Foundation (1953), Chapter 16 "Beginning of War"
Source: Empire novels (1950–1952), Pebble in the Sky (1950), Chapter 1 "Between One Footsep and the Next" (p. 6)