Number | Name | Date | Kind |
---|---|---|---|
1740835 | Riderich | Dec 1929 | |
2120727 | Bell | Jun 1938 | |
2146544 | Kleine | Feb 1939 | |
3111675 | Mora | Nov 1963 | |
3421233 | Gaal | Jan 1969 |
Number | Date | Country |
---|---|---|
1,000,379 | Oct 1951 | FR |
1,175,873 | Nov 1958 | FR |
271,764 | Feb 1930 | IT |
Entry |
---|
"The Perception of Brightness and Darkness," Leo M. Hurvich et al., 1966. |