Whitlock, R. H., Hutchinson, L. T., Glickman, L. T., Meinersmann, R., Rossiter, C., Bruce, J., Merkal, R. and Dick, J. (1986) “Paratuberculosis (Johne’s disease) update”, The Bovine Practitioner, (21), pp. 24–30. doi: 10.21423/bovine-vol0no21p24-30.