1. Brooks G.F., Butel J.S., Morse S.A. (2004) Medical Microbiology, 23rdEd., Alange Medical Books, Mc Graw Hill, Boston, p. 262.
2. Burrell R. (1979) Experimental Immunology, 5thed., Burgess Publishing co., Minneapolis.
3. Cruickshank R., Doguid J.P., Marimoin B.P., Swain R.H.A. (1974)In: Medical Microbiology, Vol.2, Churchill Livingstone, London, 319–339.