B. Tversky, S. Lozano, J. Heiser, P. Lee, and M. Daniel. AAAI Spring Symposium: Reasoning with Mental and External Diagrams: Computational Modeling and Spatial Assistance, page 105-107. AAAI, (2005)
B. Tversky, J. Heiser, P. Lee, and M. Daniel. Spatial Language and Dialogue, volume 3 of Explorations in language and space, Oxford University Press, (2009)