1. Bakhshalizade, S., Brojerdian, N., Dehghani, Z., Didehvar, F., Taheri, M., Alamian, V., et al. (2008). Mathematics 1. Tehran: The general bureau for textbook printing and distribution, Ministry of Education.
2. Bao, J. (2004). A comparative study on composite difficulty between new and old Chinese mathematics textbooks. In L. Fan, N.-Y. Wong, J. Cai, & S. Li (Eds.), How Chinese learn mathematics (pp. 208–227). Singapore: World Scientific.
3. Borromeo Ferri, R. (2006). Theoretical and empirical differentiations of phases in the modelling process. Zentralblatt für Didaktik der Mathematik, 38(2), 86–95.
4. de Lange, J. (2003). Mathematics for literacy. In B. Madison & L. Steen (Eds.), Quantitative literacy: Why numeracy matters for schools and colleges (pp. 75–89). New Jersey: The National Council on Education and the Disciplines.
5. Fan, L. (1999). Application of arithmetic in US and Chinese textbooks: A comparative study. In G. Kaiser, E. Luna, & I. Huntley (Eds.), International comparisons in mathematics education (pp. 151–164). London: Routledge.