De Koeijer A.A., Hagenaars T.J., Elbers A.R.W., Gethmann J.M., Meroc E., Guis H., Boender G.. 2012. In : 13th International Symposium on Veterinary Epidemiology and Economics : Book of abstracts. Wageningen : Wageningen Academic Publishers, p. 222-222. International Symposium on Veterinary Epidemiology and Economics. 13, 2012-08-20/2012-08-24, Maastricht (Pays-Bas).