1. Cabe, P. A. Representation of dihedral edges by lines in drawings for pigeons. Unpublished data.
2. Cabe, P. A., & Eckerman, D. A. Object features and line depiction for pigeons. Unpublished data.
3. Cerella, J. Absence of occlusion processing in the pigeon. Unpublished manuscript.
4. Problems of pictorial perception;Adams;Leonardo,1977
5. Visual pattern analysis in machines and animals;Barlow;Science,1972