Graham Philip L, LaRussa Philip S, Kohl Katrin S
Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, NY, USA; Department of Epidemiology, New York Presbyterian Hospital, New York, NY, USA.
Vaccine. 2007 Aug 1;25(31):5763-70. doi: 10.1016/j.vaccine.2007.04.063. Epub 2007 May 11.