Alamillo JM, Saénz P, García JA. Salicylic acid-mediated and RNA-silencing defense mechanisms cooperate in the restriction of systemic spread of plum pox virus in tobacco. Plant J. 2006 Oct;48(2):217–27. doi: 10.1111/j.1365-313x.2006.02861.x. PMID: 17018032.