This is a continuation of application Ser. No. 636,071, filed Nov. 28, 1975, now abandoned.
Number | Name | Date | Kind |
---|---|---|---|
2438197 | Wheeler | Mar 1948 | |
3418572 | Humphreys | Dec 1968 | |
3740742 | Thompson et al. | Jun 1973 | |
3836842 | Zimmermann et al. | Sep 1974 |
Number | Date | Country |
---|---|---|
219,493 | Apr 1957 | AUX |
Entry |
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Eggleston, H., Locating Underground Pipes, Journal of the Southern California Meter Assoc., Instruments, vol. 24, Issue 1, Jan. 1951, pp. 105-108, 110. |
Lougheed et al., Buried Marking of Point Locations, IEEE Transactions on Instrumentation and Measurement, vol. IM-22, No. 4, pp. 399-402, Dec. 1973. |
Number | Date | Country | |
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Parent | 636071 | Nov 1975 |