Houghton Mifflin Company. (2002). Houghton Mifflin mathematics. Houghton Mifflin.
Cita Chicago (17th ed.)Houghton Mifflin Company. Houghton Mifflin Mathematics. Boston: Houghton Mifflin, 2002.
Cita MLA (8th ed.)Houghton Mifflin Company. Houghton Mifflin Mathematics. Houghton Mifflin, 2002.
Atenció: Aquestes cites poden no estar 100% correctes.