Descriptive analyses of maternally-derived antibody levels against porcine circovirus 2 (PCV-2) in 3- and 21-day-old piglets from farms of four European countries using different v... oleh M. Sibila, A. Llorens, E. Huerta, C. Fablet, M. Faderl, L. Ferrari, N. Rose, A. Palzer, P. Martelli, M. C. Venegas-Vargas, D. Fredrickson, L. Taylor, M. Balasch, M. Bandrick, J. Segalés