1. Levinson, B. M. (1975). Pets and environment. In: Anderson, R. S. (ed.). Pet Animals and Society ,pp. 8–18 (London: Balliere Tindall)
2. Carding, A. (1975). The growth of pet population in Western Europe and the implications for dog control in Great Britain. In: Anderson, R. S. (ed.). Pet Animals and Society ,pp. 66–88 (London: Balliere Tindall)
3. Jenner, E. (1798). An enquiry into the cause and effects of the variolae vaccinae ,p. 2. (London: Published by the author)
4. Walters, T. M. H. (1978). Hydatid disease in Wales: 1. Epidemiology. Vet. Record ,102, 257
5. Clarkson, M. J. (1978). Hydatid disease in Wales: 2. Eradication. Vet. Record ,102, 259