Hong Li Yang Jin Song Dong Ke Gang Hao Jun Gang Han Formalizing Semantics of XSLT Using Object-Z. 120-131 2003 conf/apweb/2003 APWeb http://link.springer.de/link/service/series/0558/bibs/2642/26420120.htm db/conf/apweb/apweb2003.html#YangDHH03