Kenna, L. A. (1962). Understanding mathematics with visual aids. Littlefield, Adams and Co.
Cita Chicago (17th ed.)Kenna, L. A. Understanding Mathematics with Visual Aids. New Jersey: Littlefield, Adams and Co, 1962.
Cita MLA (9th ed.)Kenna, L. A. Understanding Mathematics with Visual Aids. Littlefield, Adams and Co, 1962.
Atenció: Aquestes cites poden no estar 100% correctes.