In "Ballad of Frida Suarez", when Frida arrives on stage, her band mate asks if she has finished the song. Frida says, "No. It's a blues riff in B. Watch me for the changes and try to keep up." This is the same thing Marty McFly says to the band before he sings "Johnny B. Goode" in the first
Back to the Future (1985) movie.