diff --git a/make-includes/build_document_rules.make b/make-includes/build_document_rules.make
index bdcf503..efc2275 100755
--- a/make-includes/build_document_rules.make
+++ b/make-includes/build_document_rules.make
@@ -124,6 +124,13 @@
 	$(PRINT_QUESTIONS_PDF_2UP) $(PRINT_ANSWERS_PDF_2UP)
 
 
+#
+# List of XSL stylesheets. If any of these change, we need to rebuild everything.
+#
+#XSLT_STYLESHEETS:=$(shell java org.apache.xml.resolver.apps.resolver -u file:///xml2html.xsl uri | ( grep 'Result: file:' || echo '::xml2html.xsl' ) | cut -d':' -f3-) $(shell java org.apache.xml.resolver.apps.resolver -u file:///xml2latex.xsl uri | ( grep 'Result: file:' || echo '::xml2latex.xsl' ) | cut -d':' -f3-)
+XSLT_STYLESHEETS=$(TEACHING_SHARED)/Authoring/XML/xml2html.xsl $(TEACHING_SHARED)/Authoring/XML/xml2latex.xsl
+
+
 ################################################################################
 #
 # Extract the list of included filenames from the source template. Hooray
@@ -281,7 +288,7 @@
 # fragments. XInclude 1.0 supports this, but it's only just been finalised
 # at the time of writing (January 2005).
 #
-$(DERIVED_XML): $(SOURCE_XML)
+$(DERIVED_XML): $(SOURCE_XML) $(XSLT_STYLESHEETS)
 	@announce "Generating $@"
 	@echo "<!-- THIS FILE IS AUTOMATICALLY GENERATED. DO NOT EDIT! -->" > $@
 	@echo >> $@