APA (7e ed.) Bronvermelding

UNDERHILL, R. G. (1977). Teaching elementary school mathematics.-- ed.2. Charles E.Merill pub.

Chicago (17e ed.) Bronvermelding

UNDERHILL, Robert G. Teaching Elementary School Mathematics.-- Ed.2. Columbus: Charles E.Merill pub, 1977.

MLA (9e ed.) Bronvermelding

UNDERHILL, Robert G. Teaching Elementary School Mathematics.-- Ed.2. Charles E.Merill pub, 1977.