1. Downing, L. A., Bernstein, J. M., and Walter, A. (1992),J. Virol. Meth. 38, 215–228.
2. Barteling, S. J., Sugimori, T., and De Leeuw, P. W. (1979),Bull. Off. Int. Epiz. 91,(1-2), 101–117.
3. Morrow, A. W., Whittle, C. J., and Eales, W. A. (1974),Bull. Off Int. Epiz. 81(11-12), 1155–1167.
4. Lei, J.C. (1974),Bull Off. Int. Epiz. 81(11-12), 1169–1199.
5. Morrow A. W. (1975),Amicon B. V. Technical Publication Nbr 12.