Recognition and semi-differential invariants. - Luc Van Gool; P. Kempenaers; André Oosterlinck (CVPR, 1991)

Recognition of planar shapes under affine distortion. - Eric J. Pauwels; Theo Moons; Luc Van Gool; P. Kempenaers; André Oosterlinck (Int. J. Comput. Vis., 1995)