Hänvisningar finns i följande patent|
| US4184854 | 24 apr 1978 | 22 jan 1980 | Norton Company | Magnetic cores for diamond or cubic boron nitride grinding wheels | | US4411107 | 3 dec 1980 | 25 okt 1983 | Disco Co., Ltd. | Grinding wheel for flat plates | | US4545154 | 15 aug 1983 | 8 okt 1985 | Disco Co., Ltd. | Grinding wheel for flat plates |
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