1. W. V. Quine, Word and Object, 1960, p. 264.
2. W. V. Quine, From a Logical Point of View, 2nd rev. ed., 1961, p. 2.
3. K. R. Popper, “What is Dialectic?” in Conjectures and Refutations, 1963.
4. K. R. Popper, The Poverty of Historicism, 1957, Preface.
5. H. Weyl, The Theory of Groups and Quantum Mechanics, 1931, pp. 72 and 393.