1. Raeumliches Vorstellungsvermoegen, Lang, Frankfurt, 1984.
2. Spatial ability?Its educational and social significance. London: University of London, 1964.
3. Spatial Visualization—A Gateway to Computer-Based Technology
4. and Identifying gender differences in the 3D visualization skills of engineering students in Brazil and in the United States. Proceedings of the International Conference for Engineering Education 1998, Rio de Janeiro, Brazil, 1998.