APA (7e ed.) Bronvermelding

Butler, C. H. 1., & Wren, F. L. 1. (1960). The teaching of secondary mathematics (3d ed.). McGraw-Hill.

Chicago (17e ed.) Bronvermelding

Butler, Charles H. 1894, en Frank Lynwood 1894 Wren. The Teaching of Secondary Mathematics. 3d ed. New York: McGraw-Hill, 1960.

MLA (9e ed.) Bronvermelding

Butler, Charles H. 1894, en Frank Lynwood 1894 Wren. The Teaching of Secondary Mathematics. 3d ed. McGraw-Hill, 1960.