REFERENCES
- Healey , C. 1993 . Build-a-Book Geometry . Emeryville CA : Key Curriculum Press .
- Boelkins , M. and T. Ratliffe . 2001 . How We Get Our Students to Read the Text Before Class . FOCUS. 21 ( 1 ): 16 – 17
- Castellanos, J. Non-Euclid Applet . http://cs.unm.edu/∼joel/Non-Euclid/ .