Empiricism, Semantics, and Ontology - Full text of the major paper by philosopher Rudolph Carnap, first published in Revue Internationale de Philosophie 4 in 1950.
Logical Foundations of Probability - Full text of the 1950 paper by philosopher Rudolph Carnap, analayzing the function and design of explanations.
Wikipedia: Rudolf Carnap - User-created article on philosopher Rudolph Carnap. Gives a biography of Carnap, and examines his relationship to other major philosophers of the 20th century.