diff --git a/Makefile b/Makefile
index 01c75b8..b9519c2 100755
--- a/Makefile
+++ b/Makefile
@@ -53,7 +53,7 @@
 MODULES:=$(shell $(FIND) modules -type f -name "*.xml" )
 
 
-all: xml2html.xsl xml2xhtml.xsl xml2latex.xsl xml2xelatex.xsl oracle-docs.xsl
+all: xml2html.xsl xml2xhtml.xsl xml2latex.xsl xml2xelatex.xsl oracle-docs.xsl calendar_dates.xsl
 
 
 xml2html.xsl xml2latex.xsl xml2xelatex.xsl: format-master.xml $(MODULES) xml2xslt.xsl oracle-docs.xsl Makefile
@@ -66,6 +66,10 @@
 	$(call xslt,$<,xml2xslt.xsl,$(call xslt_parameter,target-format,$(@:xml2%.xsl=%))) > $@
 
 
+calendar_dates.xsl: generate_calendar_dates.php
+	php $< > $@
+
+
 oracle-docs.xsl: oracle-docs.perl
 	perl $< '.*' xslt > $@