1. Acredolo, C. (1982). Conservation—nonconservation: Alternative explanations. In C. J. Brainerd (Ed.), Children’s logical and mathematical cognition (pp. 1–31). New York: Springer.
2. Barrett, J. E., Jones, G., Thornton, C., & Dickson, S. (2003). Understanding children’s developing strategies and concepts for length. In D. H. Clements & G. Bright (Eds.), Learning and teaching measurement (pp. 17–30). Reston, VA: National Council of Teachers of Mathematics. 2003 Yearbook.
3. Battista, M. T. (2006). Understanding the development of students’ thinking about length. Teaching Children Mathematics, 13(3), 140–146.
4. Benz, C. (2012, July 8–15). Learning to see—Representation, perception and judgement of quantities of numbers as a task for in-service teacher education in preschool education. Paper presented at the 12th international congress on mathematical education, Seoul, Korea.
5. Benz, C., Peter-Koop, A., & Grüßing, M. (2015). Frühe mathematische Bildung. Mathematiklernen der Drei-bis Achtjährigen [Early mathematical education]. Heidelberg: Springer.