Qualitative Outline Theory. - Antony Galton; Richard C. Meathrel (IJCAI, 1999)

Qualitative Representation of Planar Outlines. - Richard C. Meathrel; Antony Galton (ECAI, 2000)

A Hierarchy of Boundary-based Shape Descriptors. - Richard C. Meathrel; Antony Galton (IJCAI, 2001)