Tal J., Fujita D. J., Kawai S., Varmus H. E., Bishop J. M. Purification of DNA complementary to the env gene of avian sarcoma virus and analysis of relationships among the env genes of avian leukosis-sarcoma viruses (англ.) // J Virol.[англ.] : journal. — 1977. — Vol. 21, no. 2. — P. 497—505. — PMID189084.
Tal J., Fujita D. J., Kawai S., Varmus H. E., Bishop J. M. Purification of DNA complementary to the env gene of avian sarcoma virus and analysis of relationships among the env genes of avian leukosis-sarcoma viruses (англ.) // J Virol.[англ.] : journal. — 1977. — Vol. 21, no. 2. — P. 497—505. — PMID189084.