Population diversity among Bordetella pertussis isolates, United States, 1935-2009. - Schmidtke AJ; Boney KO; Martin SW; Skoff TH; Tondella ML; Tatti KM; Schmidtke, Amber J; Boney, Kathryn O; Martin, Stacey W; Skoff, Tami H; Tondella, M Lucia; Tatti, Kathleen M (Emerging Infectious Diseases, 2012)