1. Openaccess API. http://www.si2.org/.
2. Volume of an n-ball. http://en.wikipedia.org/wiki/Volume_of_an_n-ball.
3. International Technology Roadmap for Semiconductors(ITRS). http://www.itrs.net/, 2009.
4. Multidimensional binary search trees used for associative searching
5. Benno Bueler and Andreas Enge. VINCI version 1.0.5. http://www.math.u-bordeaux1.fr/~aenge/software/vinci/manual.pdf.