NUCLEIC ACIDS RESEARCH, vol. 29, no. 24, page. 5009 - 5016, 2001-12-15
JOURNAL OF MOLECULAR BIOLOGY, vol. 304, no. 2, page. 119 - 133, 2000-11-24
VIROLOGY, vol. 196, no. 2, page. 739 - 747, 1993-10