Columbia subject headings:
Harvard subject headings:
Frege, Gottlob, 1848-1925.
Logic, Symbolic and mathematical.
Philosophy.
Stumpf, Carl, 1848-1936.
Princeton subject headings:
Frege, Gottlob, 1848-1925.
Logic, Symbolic and mathematical.
Philosophy.
Stumpf, Carl, 1848-1936.