http://www.w3.org/TR/xsl11/#datatype (标准)
http://antennahouse.com/xslfo.htm
http://www.schemacentral.com/sc/fo11/s-fo.xsd.html (fo的xsd，非官方)
http://xmlgraphics.apache.org/fop/fo.html
http://www.ibm.com/developerworks/cn/xml/x-xslfo2app/
http://xml.ascc.net/zh/UTF-8/faq.html (简绍XML知识的)
http://www.cafeconleche.org/books/bible2/chapters/ch18.html
http://www.cafeconleche.org/books/bible3/chapters/ch16.html (xml-bible)
http://www.renderx.com/tutorial.html
https://www.ecrion.com/help/support/pdf/xsl-fotutorial.pdf
http://xmlgraphics.apache.org/fop/1.1/embedding.html#config-external
http://www.htm2pdf.co.uk/ (在线HTML转PDF，仅支持英文)