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SPARLIN DERRY D

US3 patents

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US5355949AOct 18, 1994

Well liner with dual concentric half screens

SPARLIN DERRY D66 citations95

US4771829ASep 20, 1988

Well liner with selective isolation screen

SPARLIN DERRY D88 citations95

US5355948AOct 18, 1994

Permeable isolation sectioned screen

SPARLIN DERRY D48 citations92