| Number | Name | Date | Kind |
|---|---|---|---|
| 1980783 | Cook et al. | Nov 1934 | |
| 4231575 | Kutt et al. | Nov 1980 | |
| 4408760 | Ferrari | Oct 1983 | |
| 4568084 | Mott | Feb 1986 | |
| 4684131 | Mortvedt | Aug 1987 | |
| 4907810 | Whitehead | Mar 1990 |
| Number | Date | Country |
|---|---|---|
| 544572 | Feb 1932 | DE2 |
| 2757971 | Jun 1979 | DEX |
| 976198 | Oct 1950 | FRX |
| Entry |
|---|
| "String Pattern Moves Sweet Spot", The Sporting Goods Dealer, 1978 p. 150. |