Banerjee, R., & Subramaniam, K. (2012). Evolution of a Teaching Approach for Beginning Algebra. Educational Studies in Mathematics, 80, 351-367. http://dx.doi.org/10.1007/s10649-011-9353-y
 Behr, M., Erlwanger, S., & Nichols, E. (1980). How Children View the Equals Sign. Mathematics Teaching, 92, 13-18.
 Booth, L. R. (1984). Algebra: Children’s Strategies and Errors. Windsor, UK: NFER-Nelson.
 Booth, L. R. (1988). Children’s Difficulties in Beginning Algebra. In A. F. Coxford (Ed.), The Ideas of Algebra, K-12 (1988 Yearbook, pp. 20-32). Reston, VA: National Council of Teachers of Mathematics.
 Cai, J., & Moyer, J. (2008). Developing Algebraic Thinking in Earlier Grades: Someinsights from International Comparative Studies. In C. Greenes, & R. Rubenstein (Eds.), Algebra and Algebraic Thinking in School Mathematics (70th Yearbook of the National Council of Teachers of Mathematics, pp.169-180). Reston, VA: NCTM.
 Cai, J., Lew, H. C, Morris, A., Mover, J. C, Ng, S. F., & Schmittau, J. (2004). The Development of Students’ Algebraic Thinking in Earlier Grades: A Cross-Cultural Comparative Perspective. Paper Presented at the Annual Meeting of the American Educational Research Association, San Diego, CA.
 Carry, L. R., Lewis, C., & Bernard, J. (1980). Psychology of Education Solving: An Information Processing Study. Austin: University of Texas at Austin, Department of Curriculum and Instruction.
 Chaiklin, S. (1989). Cognitive Studies of Algebra Problem Solving and Learning. In S. Wagner, & Kieran (Eds.), Research Issue in Learning and Teaching of Algebra (pp. 93-114). Reston, VA: National Council of Teachers of Mathemaics; Hillsdale, NJ: Lawrence Erlbaum.
 Davis, R. B. (1975). Cognitive Processes Involved in Solving Simple Algebraic Equations. Journal of Children’s Mathematical Behaviour, 1, 7-35.
 Falkner, K., Levi, L., & Carpenter, T. P. (1999). Children’s Understanding of Equality Foundation for Algebra. Teaching Children Mathematics, 6, 232-237.
 Filloy, E., & Rojano, T. (1989). Solving Equations: The Transition from Arithmetic to Algebra. For the Learning of Mathematics, 9, 19-25.
 Fischbein, E., & Barash, A. (1993). Algorithmic Models and Their Misuse in Solving Algebraic Problems. Proceedings of PME 17, 1, 162-172.
 Freiman, V., & Lee, L. (2004). Tracking Primary Students’ Understanding of Equal Sign. In M. Hoines, & A. Fuglestad (Eds.), Proceedings of the 28th Conference of the International Group for the Psychology of Mathematics Education (pp. 415-422). Bergen: PME.
 Greeno, J. G. (1982). A Cognitive Learning Analysis of Algebra. The Annual Meeting of the American Educational Research Association, Boston, MA.
 Herscovics, N. (1989). Cognitive Obstacles Encountered in the Learning of Algebra. In S. Wagner, & C. Kieran (Eds.), Research Issues in the Learning and Teaching of Algebra (pp. 60-86). Reston, VA: National Council of Teachers of Mathematics; Hillsdale, NJ: Lawrence Erlbaum.
 Herscovics, N., & Linchevski, L. (1994). A Cognitive Gap between Arithmetic and Algebra. Educational Studies in Mathematics, 27, 59-78. http://dx.doi.org/10.1007/BF01284528
 Hoz, R., & Harel, G. (1989). The Facilitating Role of Table Form in Solving Algebra Speed Problems: Real or Imaginary? In G. Vergnaud, J. Rogalski, & M. Artigue (Eds.), Proceeding of the 13th International Conference for the Psychology of Mathematics Education (pp. 123-130). Paris: G. R. Didactique, CNRS.
 Khng, K. H., & Lee, K. (2009). Inhibiting Interference from Prior Knowledge: Arithmetic Intrusions in Algebra Word Problem Solving. Learning and Individual Differences, 19, 262-268. http://dx.doi.org/10.1016/j.lindif.2009.01.004
 Kieran, C. (1992). The Learning and Teaching of School Algebra. In D. Grouws (Ed.), Handbook of Research on Mathematics Teaching and Learning (pp. 390-419). New York: Macmillan Publishing Company.
 Kieran, C. (2004). Algebraic Thinking in the Early Grades: What Is It? The Mathematics Educator, 8, 139-151.
 Kiichemann, D. (1981). Algebra. In K. M. Hart (Ed.), Children’s Understanding of Mathematics (pp. 11-16). London: John Murray.
 Kilpatrick, J., Swafford, J., & Findell, B. (2001). Adding It Up: Helping Children Learn Mathematics. Washington, DC: National Academy Press.
 Li, X., Ding, M., Capraro, M. M., & Capraro, R. M. (2008). Sources of Differences in Children’s Understandings of Mathematical Equality: Comparative Analysis of Teacher Guides and Student Texts in China and the United States. Cognition and Instruction, 26, 195-217. http://dx.doi.org/10.1080/07370000801980845
 Linchevski, L., & Herscovics, N. (1996). Crossing the Cognitive Gap between Arithmetic and Algebra: Operating on the Unknown in the Context of Equations. Educational Studies in Mathematics, 30, 39-65.
 Napaphun, V. (2012). Relational Thinking: Learning Arithmetic in Order to Promote Algebraic Thinking. Journal of Science and Mathematics Education in Southeast Asia, 35, 84-101.
 Ng, S. F., & Lee, K. (2009). The Model Method: Singapore Children’s Tool for Representing and Solving Algebraic Word Problems. Journal for Research in Mathematics Education, 40, 282-313.
 Rachlin, S. L. (1989). Using Research to Design a Problem-Solving Approach for Teaching Algebra. In S. T. Ong (Ed.), Proceedings of the 4th Southeast Asian Conference on Mathematical Education (pp. 156-161). Singapore: Singapore Institute of Education.
 Radford, L. (2012). Early Algebraic Thinking Epistemological, Semiotic, and Developmental Issues. 12th International Congress on Mathematical Education, Seoul, South Korea.
 Radford, L., & Puig, L. (2007). Syntax and Meaning as Sensuous, Visual, Historical forms of Algebraic Thinking. Educational Studies in Mathematics, 66, 145-164. http://dx.doi.org/10.1007/s10649-006-9024-6
 Reed, S. K. (1987). A Structure-Mapping Model for Word Problems. Journal of Experimental Psychology: Learning, Memory and Cognition, 13, 124-139. http://dx.doi.org/10.1037/0278-73184.108.40.206
 Reed, S. K., Dempster, A., & Ettinger, M. (1985). The Usefulness of Analogous Solution for Solving Algebra Word Problems. Journal of Experimental Psychology: Learning, Memory and Cognition, 11, 106-125.
 Sadovsky, P., & Sessa, C. (2005). The Adidactic Interaction with the Procedures of Peers in the Transition from Arithmetic to Algebra: A Milieu for the Emergence of New Questions. Educational Studies in Mathematics, 59, 85-112.
 Sfard, A. (1991). On the Dual Nature of Mathematical Conceptions: Reflections on Processes and Objects as Different Sides of the Same Coin. Educational Studies in Mathematics, 22, 1-36. http://dx.doi.org/10.1007/BF00302715
 Sfard, A., & Linchevski, L. (1993). Processes without Objects—The Case of Equations and Inequalities. The Special Issue of del Seminario Matematico de U’Universita edel Politecnico di Torino.
 Sfard, A., & Linchevski, L. (1994). The Gains and the Pitfalls of Reification—The Case of Algebra. Educational Studies in Mathematics, 26, 191-228. http://dx.doi.org/10.1007/BF01273663
 Wang, X. (2014). The Transition from Arithmetic to Algebra: Cognitive Gap, Prealgebraic Conceptualization, and Teacher Preparation. Edmonton: University of Alberta. (Unpublished Essay).
 Welder, R. M. (2012). Improving Algebra Preparation: Implications from Research on Student Misconceptions and Difficulties. School Science and Mathematics, 112, 255-264. http://dx.doi.org/10.1111/j.1949-8594.2012.00136.x
 Wenger, R. (1987). Cognitive Science and Algebra Learning. In A. Schoenfeld (Ed.), Cognitive Science and Mathematics Education (pp. 217-251). Hillsdale, NJ: Lawrence Erlbaum.