have taken place. But on the other hand, I understood Sean's anger, and believe me, I have wanted to hit him many times. I never would you know, because I realize that it would just make things worse. [...] I felt like he was 'Causing a Commotion' to purposefully distract me. I wrote this song and vented my frustration in it." The last song developed was "Can't Stop", a track inspired by Sixties Motown and the group Martha and the Vandellas. In addition to this, the album also included tracks by some acts on Warner Bros. Records, namely Club Nouveau, Scritti Politti and Michael Davidson. Commercially unsuccessful and unknown in the US, these groups needed a platform to project their songs, and including them in a Madonna album seemed like the right thing to do for Warner. Two tracks by Duncan Faure and Coati Mundi were included on the soundtrack at the request of Madonna since they were her friends. Despite her only performing four of the nine tracks on the album, Who's That Girl was marketed as a Madonna album, with only her face and name appearing on the cover art. Composition The title track is composed in Madonna's typical style—mixing a drum machine, bubbling bass synth line, and the sound of stringed instruments. According to Rikky Rooksby, author of The Complete Guide to the Music of Madonna, the three parts of the song, namely the bridge, where Madonna sings "what can help me now", the chorus and the verse flow together in a coherent manner, with the chorus incorporating a haunting effect. The song epitomized Madonna's interest in Hispanic culture that continued after the release of her 1987 single "La Isla Bonita". Leonard and Madonna had added Spanish phrases in the chorus, over the trumpets of the second verse, and also in the added instrumental break in the middle. "Who's That Girl" also makes use of the sonic effect brought about by the combination of multiple vocal lines, which had been previously used by groups like The Beach Boys in their singles "God Only Knows" (1966) and "I Get Around" (1964) as well as R.E.M.'s singles "Fall on Me" (1986) and "Near Wild Heaven" (1991). "Who's That Girl" employs this effect on the last chorus where three or four different vocal hooks are intertwined. The second track "Causing a Commotion" has a danceable, up-tempo groove. The musical arrangement