1. Burgdorfer, W., 1975. A review of Rocky Mountain spotted fever (tick-borne Typhus), its agent, and its tick vectors in the United States. J. Med. Entomol., 12:269?278.
2. Carroll, J.H. and Schmidtman, E.T., 1986. Summer activity of the American dog tick (Acari: Ixodidae), summer activity on equine premises enzootic for Potomac horse fever in south-central Maryland. J. Econ. Entomol., 79:62?66.
3. Fletcher, M.G., 1987. Determination of the possible role of arthropods as vectors for Potomac horse fever. Ph.D. thesis, Virginia Polytechnic and State University, Blacksburg, VA, 96 pp.
4. Fletcher, M.G., Rice, R.M., Perry, B.D., Turner, E.C., Hahn, N.E., Hansen, J.W., 1989. The suitability of two strains of laboratory mice for vector studies ofEhrlichia risticii. Am. J. Vet. Res. (in press).
5. Hayes, S.F. and Burgdorfer, W., 1981. Ultrastructural comparison ofWolbachia-like symbiotes of ticks. In: W. Burgdorfer and R.L. Anacker (Editors), Rickettsiae and Rickettsial Diseases. Academic Press, New York, pp. 281?289.