Columbia subject headings:
Harvard subject headings:
Arithmetic--Foundations
Hartmann, Nicolai, 1882-1950
Mathematics--Philosophy
Space and time.
Ströker, Elisabeth. Zahl und Raum.
Princeton subject headings:
Arithmetic--Foundations.
Hartmann, Nicolai, 1882-1950.
Mathematics--Philosophy.
Space and time.
Ströker, Elisabeth. Zahl und Raum.