XSLT lookup from external xml file
问题 I am aware that there are plenty of questions (and answers) here on the lookup from external xml files via xslt. However, I still haven't got my head around the logic of the key function so I'm having a hard time applying other solutions to my use case. I have two xml files: versA.xml <TEI> <div> <l id="A001" corresp="B001">First line of VersA</l> <l id="A002" corresp="B002">Second line of VersA</l> <l id="A003" corresp="B003">Third line of VersA</l> </div> </TEI> and versB.xml <TEI> <div> <l