1. Bochev I (2007) Porcine respiratory disease complex (PRDC): a review. I. Etiology, epidemiology, clinical forms and pathoanatomical features. Bulgarian J Vet Med 10:131–146
2. Zhao P, zheng YS, Liu JW, Li RF, Yao SX, Liu XY (2010) Diagnosis of P. multocida infection secondary to swine influenza. Guangdong Agric Sci 2:128–130
3. Han Q-G, Zhang Z-Y, Cui Y (2008) The disservices and conditions of swine influenza in China. J Jilin Agric Sci 33:49–52
4. Shope RE (1931) The etiology of swine influenza. Science 73:214–215
5. Chun JWH (1919) Influenza, including its infection among pigs. Natl Med J China 5:34–44