1. Laboratory Diagnosis of Rickettsial diseases. Report of the WHO Consultation on Laboratory Diagnosis of Rickettsial Diseases, Palermo, Italy — 1987. Bull WHO 1988; 66: 403–404.
2. Pervikov, Y. The role of the World Health Organisation in the control of rickettsial diseases. In: Kazár J, Raoult D (eds), Rickettsiae and rickettsial diseases. Bratislava: VEDA, Publishing House of the Slovak Academy of Sciences, 1991: 632–639.
3. Ormsbee, RA. A method of purifying Coxiella burnetii and other pathogenic rickettsiae. J Immunol 1962; 88: 100–108.
4. Kováčová E, Gallo J, Schramek Š, Kazár J, Brezina R. Coxiella burnetii antigens for detection of Q fever antibodies by ELISA in human sera. Acta Virol 1987; 31: 254–259.
5. Brezina R. New advances in the study of rickettsial antigens. Zbl Bakt I Abt Orig 1968; 206: 313–321.