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GB633322A
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Improvements in or relating to a system for electrical prospecting
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US2475827A
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Electrical measuring system
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US2375778A
|
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Apparatus for making geophysical explorations
|
|
US2375777A
|
|
Electrical prospecting system
|
|
US2375776A
|
|
Electrical prospecting system
|
|
US2375775A
|
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Electrical prospecting system
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US2342629A
|
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Coupling circuit
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US2342628A
|
|
Coupling circuit
|
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US2314874A
|
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Reversing switch
|
|
US2343140A
|
|
Apparatus for making geophysical explorations
|
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US2342626A
|
|
Apparatus for making geophysical explorations
|
|
US2342627A
|
|
Apparatus for making geophysical explorations
|
|
US2342676A
|
|
Frequency converter system for geophysical prospecting
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|
US2314873A
|
|
Apparatus for making geophysical explorations
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US2294395A
|
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Method and apparatus for making geological explorations
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CA449375A
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Electrical prospecting system
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CA415209A
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Geophysical exploration apparatus
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CA415208A
|
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Geological exploration apparatus
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