Remark made during a week at Princeton beginning 9 May 1921, later carved above the fireplace of the Common Room of Fine Hall (the Mathematical Institute), Princeton University - in R. W. Clark Einstein (1973) ch. 14
"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.
"The philosophy of Niels Bohr" by Aage Petersen in "Bulletin of the Atomic Scientists", Volume 19, No. 7 (September 1963), as quoted in Abraham Pais "The Genius of Science: A Portrait Gallery" (p. 24), 2000, and in Paul McEvoy "Niels Bohr: Reflections on Subject and Object" (p. 291), October 2000.
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