I have to research the syntax of xslt which is very terrible for me. But I still read some books about xslt.We have a file-pushd system which client is applied the xslt to trasform the xml to html. There is a great amount of xsl file which is such a confusion in the program of client. I have to make it clear  to edit it on the original xsl file.
I like to provide a web site which introduce a lot of  information about xslt
http://www.zvon.org/xxl/XSLTutorial/Output_chi/example74_ch5.html