Columbia subject headings:
Harvard subject headings:
Frege, Gottlob, 1848-1925.
Language and languages--Philosophy
Proposition (Logic)
Russell, Bertrand, 1872-1970
Thought and thinking.
Princeton subject headings:
Frege, Gottlob, 1848-1925.
Knowledge, Theory of--History--20th century.
Proposition (Logic)--History--20th century.
Reference (Philosophy)--History--20th century.
Russell, Bertrand, 1872-1970.
Sense (Philosophy)--History--20th century.