Number | Name | Date | Kind |
---|---|---|---|
1292326 | Jacobson | Jan 1919 | |
2725788 | Pfleger | Dec 1955 | |
3481660 | Sheldon | Dec 1969 | |
4938579 | Kempf | Jul 1990 |
Entry |
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Johnson et al "Optical System for Viewing Dielectric Smear in Printed Circuit Board Hole and Deleting the Smear" IBM Tech. Disc. Bulletin, vol. 25 #9, Feb. 1983, pp. 4513-4514. |