Diversity of luteoviruses infecting faba bean (Vicia faba L) in Morocco, and their detection by the polymerase chain reaction M. Fortass, F. van der Wilk, R.W. Goldbach, L. Bos and J.F.J.M. van den Heuvel Agronomie, 16 1 (1996) 61-68 DOI: 10.1051/agro:19960104