diff --git a/src/Makefile b/src/Makefile
index 4d95790..9bfe11d 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -370,3 +370,9 @@ CAL-MONTH-SOURCES=cal-month.scm util-tag.import.scm	\
 
 cal-month.o: cal-month.import.scm
 cal-month.import.scm: $(CAL-MONTH-SOURCES)
+
+CAL-PERIOD-SOURCES=cal-period.scm cal-month.import.scm	\
+	testing.import.scm util-tag.import.scm
+
+cal-period.o: cal-period.import.scm
+cal-period.import.scm: $(CAL-PERIOD-SOURCES)
diff --git a/src/cal-period.scm b/src/cal-period.scm
index 5d2675b..552d984 100644
--- a/src/cal-period.scm
+++ b/src/cal-period.scm
@@ -62,7 +62,6 @@
 	 (chicken string)
 	 cal-month
 	 testing
-	 configuration
 	 util-tag)
 
  ;; Type tag