1. Alvin, C., Gulwani, S., Majumdar, R., Mukhopadhyay, S.: Technical report: synthesis of problems for shaded area geometry reasoning (2017).
http://hilltop.bradley.edu/~calvin/papers/aied-full.pdf
2. Boyd, C.J., et al.: Geometry (NJ Edition). Glencoe/McGraw-Hill, New York (2006)
3. CBSE, India (2012).
http://cbse.nic.in/
4. Chew, T.: Singapore Math Challenge (Grade 5+). Frank Schaffer Publications, Greensboro (2008)
5. Coxeter, H.: Introduction to Geometry. Wiley, Hoboken (1969)