Isolation of replication-competent molecular clones of visna virus

Katherine A. Staskus, Ernest F. Retzel, Elizabeth D. Lewis, Janet L. Silsby, S. T. Sheila Cyr, Jeffrey M. Rank, Steven W. Wietgrefe, Ashley T. Haase, Ronald Cook, David Fast, Paul T. Geiser, John T. Harty, Selene H. Kong, Carol J. Lahti, Thomas P. Neufeld, Thomas E. Porter, Elizabeth Shoop, Karen R. Zachow