Rich, B. (1963). Principles & problems of plane geometry. Schaum Pub. Co.
Dyfyniad Arddull ChicagoRich, Barnett. Principles & Problems of Plane Geometry. New York: Schaum Pub. Co, 1963.
Dyfyniad MLARich, Barnett. Principles & Problems of Plane Geometry. Schaum Pub. Co, 1963.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.