1. Stern H. H.Foreign Languages in Primary Education., Revised edition , London , 28 ( 1967 ).
2. ‘PLOWDEN Report’. Department of Education and Science: Children and their Primary Schools—A Report of the Central Advisory Council for Education (England) . 1 : The Report . London , 225 ( 1967 ).
3. Stern H. H.Foreign Languages in Primary Education., Revised edition , London , ( 1967 ), 117 .
4. Stern H. H.Foreign Languages in Primary Education., Revised edition , London , ( 1967 ), 117 . See also TH. ANDERSSON: ‘The Optimum Age for Beginning the Study of Modern Languages’International Review of Education., 6, 3, pp. 298–306 (1960).