1. Rational number, ratio, and proportion;Behr,1992
2. Toward a solution of the learning paradox;Bereiter;Review of Educational Research,1985
3. Paper folding and equivalent fractions—bridging a gap;Bohan;The Arithmetic Teacher,1971
4. Thinking mathematically: Integrating arithmetic and algebra in elementary school;Carpenter,2003
5. Splitting, similarity and rate of change: A new approach to multiplication and exponential functions;Confrey,1994