1. Carnap, R. 1928. Der logische Aufbau der Welt. Berlin: Weltkreis; 2nd edn. Hamburg: Meiner, 1961; translated as The logical structure of the world. Berkeley and Los Angeles: University of California Press, 1967.
2. Carnap, R. 1934. Logische Syntax der Sprache. Wien: Springer; translated as The logical syntax of language. London: Kegan Paul, 1937.
3. Carnap, R. 1939. Foundations of logic and mathematics. In International encyclopedia of unified science, eds. O. Neurath, R. Carnap, and C. Morris, vol. I, 139–213. Chicago: University of Chicago Press.
4. Carnap, R. 1950. Empiricism, semantics, and ontology. Revue Internationale de Philosophie 4: 20–40; reprinted in (Carnap 1956a, 205–229).
5. Carnap, R. 1956a. Meaning and necessity. Second, enlarged edition. Chicago: University of Chicago Press.