1. Most references are given in the text. Except for the Tractatus,references are to page numbers. In addition to the standard abbreviations for Wittgenstein’s works, the following abbreviations are used:
2. BLA: G. Frege, The Basic Laws of Arithmetic. Exposition of the System. (Berkeley/Los Angeles, 1964).
3. BLF: L.Wittgenstein, Briefe an Ludwig von Ficker (Salzburg, 1969).
4. FBLW: G. Frege, “Briefe an Ludwig Wittgenstein”, in Wittgenstein in Focus — Im Brennpunkt: Wittgenstein,ed. B. McGuinness and R. Haller (= GrazerPhilosophische Studien,Vol 33/34) (Amsterdam/Atlanta, 1989), pp. 5–33.
5. FCP: G. Frege, Collected Papers on Mathematics, Logic, and Philosophy (Oxford, 1984).