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

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Text this: The compound equation related to the Bessel-Helmholtz equation and the Bessel-Klein-Gordon equation