5MILLS D L.NTP Architecture.Protocol and Algorithms University of Delaware[EB/OL].http://www.eecis.udel.edu/mills/database/brief/arch/arch.htm,2001-05-25.
6MILLS D.Network Time Protocol (version 3) Specification,Implementation and Analysis[R].Network Working Group ReportRFC-1305,University of Delaware,1992,113.
7David L.Mills.RFC 1305-Network Time Protocol(Version 3)Specification.Implementation,1992.
8David L.Mills.NTP Architecture.Protocol and Algorithms,2003.