APA استشهاد

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

استشهاد بنمط شيكاغو

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

MLA استشهاد

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