6SAS Institute inc.SAS/STAT software,changes and enhancements through release 6.11[M].North Carolina:SAS Institute Inc,1996.
7HU LP(胡良平).Windows SAS 6.12 & 8.0 practical statistical analysis course(Windows SAS 6.12 & 8.0实用统计分祈教程)[M].Beijing:Military Medical and science Press(北京:军事医学科学出版社),2001.
8GAO CH.HU J,ZHANG S,et al.association of polyamines in goveming the chiling sensitivity of maize genotypes[J].Plant Growth Regulation,2009,57(1):31-38.
9SAS Institute Inc. SAS/STAT software, change and enhancements. Release 6.11. SAS Institute Inc., North Carolina, 1996.