TY  - BOOK
AU  - Gregory,R.L.
AU  - Colin Blakemore
TI  - Illusion in nature and art,
SN  - 0715607558
U1  - 701.15 GRE G 
PY  - 1973///.
CY  - London : 
PB  - Duckworth, 
KW  - Optical illusions
KW  - Visual perception
ER  -