diff --git a/default.mk.in b/default.mk.in
index 2aefd56..85f23d0 100644
--- a/default.mk.in
+++ b/default.mk.in
@@ -14,7 +14,7 @@ all: $(OUTPUTS)
 clean-recurse: clean
 	@for i in $(SUBDIRS) ; do (cd $$i && $(MAKE) clean-recurse && cd ..) ; done
 clean:
-	rm -f *.html
+	rm -f *.html events.ics
 
-%.html: %.xml $(ROOT)/csc.dtd $(ROOT)/cscweb.xsl $(ROOT)/events.xml $(ROOT)/news.xml $(ROOT)/menu.xml $(ROOT)/default.mk directory.xml $(ROOT)/cow/cow
+%.html: %.xml $(ROOT)/csc.dtd $(ROOT)/cscweb.xsl $(ROOT)/xsl/*.xsl $(ROOT)/events.xml $(ROOT)/news.xml $(ROOT)/menu.xml $(ROOT)/default.mk directory.xml $(ROOT)/cow/cow
 	$(ROOT)/cow/cow $(XSLTARGS) $(ROOT)/cscweb.xsl $< > $@