| Number | Name | Date | Kind |
|---|---|---|---|
| D248425 | Darrell | Jul 1978 | |
| D273877 | Darrell | May 1984 | |
| D311913 | Schaum | Nov 1990 | |
| D315364 | Scalice et al. | Mar 1991 |
| Entry |
|---|
| Trademarks & Symbols, vol. 2, p. 87, #5, 780, 781, 782, 1973. |
| Handbook of Pictorial Symbols, p. 62--Question Marks, 1976. |