Volume 7 issue 4 of the Journal of Sociolinguistics is an excellent, highly credible source. This source gives really good information about the effect of hip-hop culture globally. The author analyzes different factors, giving a wide range of results.
My second source is from the EBSCO host, an article called "The Globalization of Hip-Hop Starts and Ends With 'Where You're At.'" Coming from EBSCO, this is a moderately credible source. It does have some great information. The article is all about the astounding effect that hip-hop has on other cultures around the world.
My least credible source is the most fun to read. It comes from a blog titled "Globalized Identity." While it may not be the most trustworthy, the author sure gets her point out. It does a lot to hear the opinions of others, biased as they may be.