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  _____     _____              __   __   ______   
 |__  //   |  ___||   ____     \ \\/ // |      \\ 
   / //    | ||__    |    \\    \ ` //  |  --  // 
  / //__   | ||__    | [] ||     | ||   |  --  \\ 
 /_____||  |_____||  |  __//     |_||   |______// 
 `-----`   `-----`   |_|`-`      `-`'   `------`  
                     `-`

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發送短信 : Power laws in the number of copies per title in libraries