diff --git a/Makefile b/Makefile
index ce32d78..46380fd 100644
--- a/Makefile
+++ b/Makefile
@@ -65,7 +65,7 @@ imports: $(BBSTOOL-DEPS)
 bbstool: $(BBSTOOL-DEPS)
 	$(CSC) -o $@ $<
 
-bbstool-static: $(BBSTOOL-SOURCES)
+bbstool-static: $(BBSTOOL-DEPS)
 	$(CSC) -static -o $@ $(BBSTOOL-SOURCES)
 
 .PHONY: clean
diff --git a/README.md b/README.md
index 74e69be..de7863d 100644
--- a/README.md
+++ b/README.md
@@ -191,6 +191,21 @@ Returns a new valid month that comes ```n``` months after ```m```. If
 
 ### Period
 
+This module implements simple calendar period handling with month
+granularity.
+
+sort-period-markers
+
+period-markers->periods
+
+periods-duration
+
+month-in-periods?
+
+periods->string
+
+periods-match
+
 ### Primes
 
 Generic Support Modules
diff --git a/period.scm b/period.scm
index a02b902..69ed9d2 100644
--- a/period.scm
+++ b/period.scm
@@ -30,11 +30,8 @@
  (
   sort-period-markers
   period-markers->periods
-  period->duration
   periods-duration
-  month-in-period?
   month-in-periods?
-  period->string
   periods->string
   periods-match
   period-tests!