1. Shaw, “The development of the child's conception of number”, Educational Review, June 1961.
2. Poleidoblocs, in No. 29, Lowenfeld.
3. Psychological Aspects of Teaching Mathematics, in No. 25, Harris.
4. Thinking behind the Rods and Blocks, Lovell, in Summer 1963.
5. The Avon Apparatus, Part 1, Jones.