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3Near-surface helium anomalies associated with faults and gas accumulations in western Pennsylvania /by Roberts, Alan A.
Published 1985Government Document Microform Book -
4Published 1986Government Document Microform Book
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11Published 1991Government Document Book
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12Published 1991Government Document Book
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13Published 1988Government Document Book
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17Published 1994Government Document Microform Book
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18Published 1994Government Document Microform Book
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