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

  ______    _____    ______      ___     _    _   
 /_   _//  |  ___|| |      \\   / _ \\  | || | || 
   | ||    | ||__   |  --  //  | / \ || | || | || 
  _| ||    | ||__   |  --  \\  | \_/ || | \\_/ || 
 /__//     |_____|| |______//   \___//   \____//  
 `--`      `-----`  `------`    `---`     `---`