Johnson, R. A. (1929). Modern geometry: An elementary treatise on the geometry of the triangle and the circle. Houghton Mifflin.
Cita Chicago (17th ed.)Johnson, Roger A. Modern Geometry: An Elementary Treatise on the Geometry of the Triangle and the Circle. Boston: Houghton Mifflin, 1929.
Cita MLA (9th ed.)Johnson, Roger A. Modern Geometry: An Elementary Treatise on the Geometry of the Triangle and the Circle. Houghton Mifflin, 1929.
Atenció: Aquestes cites poden no estar 100% correctes.