1. The development of conceptual and procedural understanding through instruction on writing number sentences;Bebout,1987
2. Sources of difficulty in the solution of verbal arithmetic problems by mildly retarded and nonretarded individuals;Bilsky;American Journal of Mental Deficiency,1986
3. Learning to learn; on training students to learn from texts;Brown;Educational Researcher,1981
4. The development of addition and subtraction problem solving skills;Carpenter,1982
5. The acquisition of addition and subtraction concepts in grade one through three;Carpenter;Journal for Research in Mathematics Education,1984