TY  - BOOK
AU  - Gregory,R.L.
AU  - Gombrich,Ernst
AU  - 
TI  - Illusion in nature and art
SN  - 0715607596
AV  - QP495 
PY  - 1973///
CY  - [London]
PB  - Duckworth
KW  - Visual perception
KW  - Optical illusions
N1  - Includes bibliographies
ER  -