diff --git a/make-includes/build_lecture_rules.make b/make-includes/build_lecture_rules.make
index 5feb900..c0f66ce 100755
--- a/make-includes/build_lecture_rules.make
+++ b/make-includes/build_lecture_rules.make
@@ -51,10 +51,10 @@
 #
 # Base file names for the various documents.
 #
-SLIDES?=$(CHAPTER)_slides
-FIGURES?=$(CHAPTER)_figures
-COMBINED?=$(CHAPTER)_combined
-NOTES?=$(CHAPTER)_notes
+SLIDES?=Chapter$(CHAPTER)slides
+FIGURES?=Chapter$(CHAPTER)figures
+COMBINED?=Chapter$(CHAPTER)combined
+NOTES?=Chapter$(CHAPTER)notes
 #
 # Standard files to be installed on the web server.
 #