1. Carlisle, D., Ion, P., Miner, R., Poppelier, N., et al.: Mathematical Markup Language (MathML) Version 2.0. W3C Recommendation (February 21, 2001)
http://www.w3.org/TR/2001/REC-MathML2-20010221/
2. Edwards, L.D.: Embodying mathematics and science: Microworlds as representations. Journal of mathematical Behavior 17, 53–78 (1998)
3. Gibson, J.: The Ecological Approach to Visual Perception. Lawrence Erblbaum Associates, Inc., Hillsdale (1986)
4. Kadar, E.E., Effken, J.: From discrete actors to goal-directed actions: Toward a process-based methodology for psychology. Philosophical Psychology 18, 353–382 (2005)
5. Knuth, D.E.: The TeX book. Addison-Wesley, Reading (1984)