| Number | Date | Country | Kind |
|---|---|---|---|
| 3613253 | Apr 1986 | DEX |
| Number | Name | Date | Kind |
|---|---|---|---|
| 3431265 | Wakeman et al. | Mar 1969 | |
| 3435039 | Wakeman et al. | Mar 1969 | |
| 3969510 | Osieka et al. | Jul 1976 | |
| 4123554 | Kawada et al. | Oct 1978 | |
| 4585795 | Linderborg | Apr 1986 |
| Entry |
|---|
| European standard draft prEN 113 published by European Committee for Standardization, p. 7. |