Henry Margenau, Roy Abraham Varghese (1992). “Cosmos, Bios, Theos: Scientists Reflect on Science, God, and the Origins of the Universe, Life, and Homo Sapiens”, p.62, Open Court Publishing
"Social Statics, or The Conditions essential to Happiness specified, and the First of them Developed" by Herbert Spencer, (Pt. II, Ch. 4 : Derivation of a First Principle, § 3), 1851.