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| US6237691 | 8 Jun 2000 | 29 May 2001 | Kelley & Sons Group International, Inc. | Method and apparatus for increasing fluid recovery from a subterranean formation |
| US6325152 | 8 Jun 2000 | 4 Dic 2001 | Kelley & Sons Group International, Inc. | Method and apparatus for increasing fluid recovery from a subterranean formation |
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Robert E. Snyder | Method and apparatus for increasing fluid recovery from a subterranean formation |
