APA (7th ed.) Citation

Hitt Espinosa, F. A., & Santos, M. (1999). Proceedings of the twenty first annual meeting: Psychology of mathematics education PME-NA XXI. ERIC.

Chicago Style (17th ed.) Citation

Hitt Espinosa, Fernando Antonio, and Manuel Santos. Proceedings of the Twenty First Annual Meeting: Psychology of Mathematics Education PME-NA XXI. Columbus: ERIC, 1999.

MLA (9th ed.) Citation

Hitt Espinosa, Fernando Antonio, and Manuel Santos. Proceedings of the Twenty First Annual Meeting: Psychology of Mathematics Education PME-NA XXI. ERIC, 1999.