| Number | Date | Country | Kind |
|---|---|---|---|
| 88 14068 | Oct 1988 | FRX |
| Number | Name | Date | Kind |
|---|---|---|---|
| 2704522 | Frieder et al. | Mar 1955 | |
| 3410036 | Brell | Nov 1968 | |
| 3978634 | Mack et al. | Sep 1976 | |
| 4584810 | Hill | Apr 1986 | |
| 4757650 | Berger | Jul 1988 |
| Number | Date | Country |
|---|---|---|
| 2626026 | Jul 1989 | FRX |
| Entry |
|---|
| Makowski, ing Z.S., "Raumliche Tragwerke Aus Stahl", Verlag Stahlersen m.b.H., Dusseldorf, 1963, p. 197 (FIG. 220k). |