Si, Yali, Andrew K. Skidmore, Tiejun Wang, Willem F. de Boer, Pravesh Debba, Albert G. Toxopeus, Lin Li, and Herbert H.T. Prins. 2009. “Spatio-Temporal Dynamics of Global H5N1 Outbreaks Match Bird Migration Patterns”. Geospatial Health 4 (1):65-78. https://doi.org/10.4081/gh.2009.211.