發送短信 : A note on Sargan densities

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