Martin, L. B. I., Pless, M. I., & Wikelski, M. (2007). Greater seasonal variation in blood and ectoparasite infections in a temperate than a tropical population of House Sparrows Passer domesticus in North America. Ibis, 149(2), 419-423. doi:10.1111/j.1474-919X.2007.00668.x.