Langford, P. (1987). Concept development in the primary school. Croom Helm.
Citazione stile Chigago Style (17a edizione)Langford, Peter. Concept Development in the Primary School. London ; New York: Croom Helm, 1987.
Citatione MLA (8a ed.)Langford, Peter. Concept Development in the Primary School. Croom Helm, 1987.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.