The song on the paper is titled "Paz sin Fronteras" which translates to "Peace without Frontiers" That song was part of a public campaign to create awareness about the violence in the society and to bring a positive message. It was a collaboration of three recording artists from Puerto Rico. The song was free to download for everyone as part of the outreach campaign.
When one of the artists saw the picture, he asked me if they could use it as the official image to promote the song, I said yes! That was my little contribution to bring peace to Puerto Rico.