http://www.youtube.com/watch?v=jOS-68QPYzs
Above is the URL of the second example for Rihanna being advertised in an advert for Renault cars.
Above is one of Rihanna's publicity advert where she raises awareness about Leukimia on a Public Service Advertisment.
Below is the second example of Rihanna singing happy Birthday for American Cancer Society. I've included it's URL.
http://www.youtube.com/watch?v=HyCWPB5vpe4
