Citations of: Carnap Rudolf. The methodological character of theoretical concepts. Minnesota studies in the philosophy of science, Volume I, The foundations of science and the concepts of psychology and psychoanalysis, edited by Feigl Herbert and Scriven Michael, University of Minnesota Press, Minneapolis 1956, pp. 38–76.Carnap Rudolf. Beobachtungssprache und theoretische Sprache. German, with German and English summaries. Logica, Studia Paul Bernays dedicata, Bibliothèque scientifique no. 34, Éditions du Griffon, Neuch'tel 1959, pp. 32–44; also Dialectica, vol. 12 , pp. 236–248