In this citation, the piece of information that is missing is the URL of the article. An MLA citation requires the URL of the article in order to allow readers to find more information about the subject. It also allows reviewers to check whether the sources used by the author are adequate and reliable. Not having an URL in your citation would make it very difficult for everyone else to find the article that you have used online.
A sentence fragment is a incomplete sentence like, one that doesn't fully explain its self. fragment = came to the house, complete = Lilly came to the house to visit.