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2. Trnka, Z., Nature, 181, 55 (1958); see also preceding communication.
3. Šterzl, J., Czechoslov. Microbiol., 3, 61 (1958); Transpl. Bull., 5, 73 (1958).
4. Hašková, V., Folia biol., 3, 129 (1957).
5. Šterzl, J., Folia microbiol. (in the press).