1. Anonymus: Wld. Hlth Org. Tech. Kep. Ser., No. 219 (WHO, Geneva) (1961).
2. Botija, C. S.: Estudios sobre la peste porcina afrioana en Espagna. Bull. Off. int. Epiz.58, 707?727 (1962).
3. Botija, C. S.: Reservorios del virus de la peste porcina africana. Investigacion del virus de la P.P.A. en los artropodos mediante la prueba de la hemoadsorcion. Bull. Off. int. Epiz.60, 895?899 (1963).
4. Botija, C. S.: Present characteristics of African swine fever in Spain. FAO/OIE International Meeting on hog cholera and African swine fever. Rome, Italy. Working Paper No. 15 (1965).
5. Burgdorfer, W.: Artificial feeding of ixodid ticks for studies on the transmission of disease agents. J. inf. Dis.100, 212?214 (1957).