The song "Baby" by Justin Bieber (featuring Ludacris) was officially released on , as the lead single from his debut studio album, My World 2.0 . The album itself was released on March 19, 2010 .
If your "long paper" refers to an academic or journalistic piece analyzing the song, its impact, or its release strategy, you would cite the single release date (January 18, 2010) as the key date for "Baby." For context, the music video premiered on YouTube a month later (February 19, 2010) and became one of the most viewed videos of the decade.