The Dickinson classification is a library classification scheme used to catalogue and classify musical compositions. It was developed by George Sherman Dickinson (1886 - 1964), and is used by many music libraries, primarily those at University at Buffalo, Vassar, and Columbia Universities.
It is fully detailed by Carol June Bradley in The Dickinson classification : a cataloguing & classification manual for music; including a reprint of the George Sherman Dickinson Classification of Musical Compositions published by Carlisle Books (1968).
References
Dickinson classification Wikipedia(Text) CC BY-SA