1. Comber, L.C. & Keeves, J.P. (1973). Science education in nineteen countries, Stockholm, Almqvist and Wiksell.
2. Duncan, W. (1989). ‘Engendering school learning: Science attitudes and achievement among girls and boys in Botswana’, Studies in Comparative and International Education, No. 16, Stockholm, Institute of International Education, University of Stockholm.
3. IEA (International Association for the Evaluation of Educational Achievement) (1988). Science achievement in seventeen countries: A preliminary report, Oxford, Pergamon Press.
4. Keeves, J.P. (ed.) (1992). The IEA study in science III: Changes in science education and achievement, 1970-1984, Oxford, Pergamon Press.
5. Kotte, D. (1992). Gender differences in science achievement in 10 countries: 1970/1971 to 1983/1984, Frankfurt/Main, Germany, Lang.