Rickettsiae and rickettsial diseases : proceedings of the 2nd International Symposium on Rickettsiae and Rickettsial Diseases held in Smolinice, Slovakia, June 21-25, 1976 - Kazar, J.; Ormsbee, R. A.; Tarasevich, I. N. (Bratislava : VEDA, Publishing House of the Slovak Academy of Sciences, 1978)