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Periodical. Shenk, Thomas E., and Paul Berg. "Isolation and Propagation of a Segment of the Simian Virus 40 Genome Containing the Origin of DNA Replication." Proceedings of the National Academy of Sciences of the United States of America 73, 5 (May 1976): 1513-1517. Article. 5 Images.. Proceedings of the National Academy of Sciences of the United States of America