Number | Name | Date | Kind |
---|---|---|---|
3692951 | Hestad et al. | Sep 1972 | |
3736383 | Le Baron | May 1973 | |
4259549 | Stehman | Mar 1981 | |
4799255 | Billinger et al. | Jan 1989 |
Entry |
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United States Department of Commerce Telephone Directory, Mar. 1987, p. VI. |
AT&T System 85 Release 2, Versions 1-4 Features Reference Manual, Issue 1 (Jul. 1987) pp. 109-1 to 109-13. |