1. Use of drawing surfaces in different collaborative settings;Bly,1988
2. Engineering and the mind's eye;Ferguson,1992
3. Amplifying the mind's eye: sketching and visual cognition;Fish;Leonardo,1990
4. Geschka, H, Schaude, G R and Schlicksupp, H (1973) Modern techniques for solving problems Chemical Engineering August pp 91–97
5. Sketches of thought;Goel,1995