Added bibliography to report depencedies in make rules.

docs/rules.mk

@@ -18,7 +18,7 @@ $(b)%.pdf: $(d)%.tex
 		$(LATEX) $^; \
 	done
 
-$(b)$(REPORT).pdf: $(d)$(DIAGRAMS).tex
+$(b)$(REPORT).pdf: $(d)$(DIAGRAMS).tex $(b)$(REPORT).bbl
 
 $(b)$(REPORT).bbl: $(d)$(REPORT).bib
 	BIBINPUTS=$(d) bibtex8 $(@:.bbl=.aux)