how many musicals have been adapted from the same source
- Romeo and Juliet: West Side Story, Roméo et Juliette
- The Phantom of the Opera: literally dozens, most famously The Phantom of the Opera (1986), Ken Hill’s Phantom, Yeston and Kopit’s Phantom
- The Wild Party: The Wild Party (LaChiusa), The Wild Party (Lippa)
- Der Besuch der alten Dame/The Visit of the Old Lady: The Visit (Kander and Ebb), Der Besuch der alten Dame (German musical)
anyone got any additions?