Παραπομπή APA

Rudoffer, S., & Baker, I. N. (1967). Mathematics observed. Hans Freudenthal.

Παραπομπή Chicago Style

Rudoffer, Stephen, και I N. Baker. Mathematics Observed. London: Hans Freudenthal, 1967.

Παραπομπή MLA

Rudoffer, Stephen, και I N. Baker. Mathematics Observed. Hans Freudenthal, 1967.