Hänvisningar finns i följande patent|
| US4421965 | 17 maj 1982 | 20 dec 1983 | | Commutator with several layers of cross-points | | US4550276 | 14 jun 1982 | 29 okt 1985 | | Buss structures for multiscene manual lighting consoles | | US5150039 | 30 okt 1990 | 22 sep 1992 | | Electrical measuring transformer |
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