 
                 Patent Grant
 Patent Grant
                     4019745
 4019745
                    | Number | Name | Date | Kind | 
|---|---|---|---|
| 3503296 | Schmoyer et al. | Mar 1970 | |
| 3654392 | Beinhocker | Apr 1972 | |
| 3843132 | Ferguson | Oct 1974 | |
| 3888491 | Bernard et al. | Jun 1975 | |
| 3895807 | Friedman | Jul 1975 | |
| 3939579 | Andrews et al. | Feb 1976 | 
| Entry | 
|---|
| Popular Science; "Games Computers Play;" vol. 197, No. 4; Oct. 1970; p. 44. |