Selle v. Gibb
741 F.2d 896 (7th Cir. 1984) - full text opinion
Selle's version of the song was never publicly distributed, but the Bee Gee's version was a single on the Saturday Night Fever Soundtrack. That album was the
best-selling soundtrack of all-time, with over 25 million copies being sold.
You can listen to both versions of the song here, as well as a video clip of the scene in Saturday Night Fever where the Bee Gees' song was used