Alarm variables for dengue outbreaks: a multi-centre study in Asia and Latin America by Bowman, LR, Tejeda, GS, Coelho, GE, Sulaiman, LH, Gill, BS, McCall, PJ, Olliaro, PL, Ranzinger, SR, Quang, LC, Ramm, RS, Kroeger, A, Petzold, MG