有一篇文章,见链接
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VJW-3Y51HYK-5&_user=520880&_rdoc=1&_fmt=&_orig=search&_sort=d&_docanchor=&view=c&_acct=C000023460&_version=1&_urlVersion=0&_userid=520880&md5=b30000b04640f5d69f0e0a300d1955e8