RT Journal Article SR Electronic T1 Human papillomavirus in head and neck cancer JF Canadian Medical Association Journal JO CMAJ FD Canadian Medical Association SP cmaj.130849 DO 10.1503/cmaj.130849 A1 Palma, David A. A1 Nichols, Anthony C. YR 2013 UL http://www.cmaj.ca/content/early/2013/12/02/cmaj.130849.abstract AB