Hänvisningar finns i följande patent|
| US4457423 | 18 maj 1981 | 3 jul 1984 | | Conveyor system | | US5473114 | 14 apr 1993 | 5 dec 1995 | Mosler, Inc. | Clear tube section for pneumatic transport tube system | | US7104734 | 16 apr 2001 | 12 sep 2006 | HP Products, Inc. | One-way pneumatic delivery system |
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