Albert Einstein (2015). “Bite-Size Einstein: Quotations on Just About Everything from the Greatest Mind of the Twentieth Century”, p.32, St. Martin's Press
"The Philosophical Writings of Niels Bohr, Volume IV: Causality and Complementarity" edited by Jan Faye and Henry J. Folse (1998); later quoted in Karen Michelle Barad "Meeting the Universe Halfway: Quantum Physics and the Entanglement of Matter and Meaning" (p. 254), 2007.