Fix problems with cleanup of documentation files
--- a/doc/Makefile.am
+++ b/doc/Makefile.am
@@ -39,4 +39,4 @@
 	$(PDFLATEX) dr
 
 clean-local:
-	rm -f *~ *.pdf *.log *.aux *.out
+	rm -f *~ *.pdf *.log *.aux *.out *.blg dr.bbl
--- a/doc/Makefile.in
+++ b/doc/Makefile.in
@@ -884,7 +884,7 @@
 	$(PDFLATEX) dr
 
 clean-local:
-	rm -f *~ *.pdf *.log *.aux *.out
+	rm -f *~ *.pdf *.log *.aux *.out *.blg dr.bbl
 
 # Tell versions [3.59,3.63) of GNU make to not export all variables.
 # Otherwise a system limit (for SysV at least) may be exceeded.
