TY  - GEN
AU  - Held,Richard
TI  - Image, object, and illusion: readings from Scientific American
SN  - 0716705052
AV  - QP495.H35 1963 
PY  - 1974///]
CY  - San Francisco
PB  - W. H. Freeman
KW  - Optical illusions
KW  - Illusions
ER  -