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| - Many of these devices are also limited in their range of applications due to such limiting factors as operating range, battery life, or the inability to selectively locate large numbers of different articles. [0006] For example, the inventions described by U.S. Pat. No. 5,289,163 issued Feb. 22, 1994 to Perez, U.S. Pat. No. 4,785,291 issued Nov. 15, 1988 to Hawthorne, U.S. Pat. No. 5,900,817 issue
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