Histopathology and the detection of avian bornavirus in the nervous system of birds diagnosed with proventricular dilatation disease - Ouyang, N; Storts, R; Tian, Y; Wigle, W; Villanueva, I; Mirhosseini, N; Payne, S; Gray, P; Tizard, I (Avian Pathol, 2009)