"Bigger"
... that a Billboard review called Justin Bieber's vocals on "Bigger" both "boyish" and "mature"?
... that a <i id="mwFIY"><a href="./Billboard_(magazine)" id="mwFIc" rel="mw:WikiLink" title="Billboard (magazine)">Billboard</a></i> review called <a href="./Justin_Bieber" id="mwFIg" rel="mw:WikiLink" title="Justin Bieber">Justin Bieber</a>'s vocals on <b id="mwFIk">"<a class="mw-redirect" href="./Bigger_(Justin_Bieber_song)" id="mwFIo" rel="mw:WikiLink" title="Bigger (Justin Bieber song)">Bigger</a>"</b> both "boyish" and "mature"?