Columbia subject headings:
Frege, Gottlob, 1848-1925. Logische Untersuchungen.
Logic, Symbolic and mathematical.
Harvard subject headings:
Frege, Gottlob, 1848-1925. Logische Untersuchungen.
Logic, Symbolic and mathematical.
Princeton subject headings:
Frege, Gottlob, 1848-1925. Logische Untersuchungen.
Logic, Symbolic and mathematical.