diff --git a/Makefile.sphinx b/Makefile.sphinx
index 0af4b0f..c8748cd 100644
--- a/Makefile.sphinx
+++ b/Makefile.sphinx
@@ -1,53 +1,53 @@
 # Makefile to be included by other modules, from the TOPLEVEL/docs/ dir, to
 # automatically build sphinx documentation.
 
 APIDOC_DIR = apidoc
 APIDOC_OPTS = --ext-viewcode --separate
 SPHINXBUILD = sphinx-build
 SPHINXAPIDOC = sphinx-apidoc
 SPHINX_OPTS =
 SPHINX_BUILDDIR = _build
 SPHINX_SRCDIR = .
 
 # relative to docs/ dir. Hence "." exclude the docs/ dir itself
 APIDOC_EXCLUDES = conftest.py setup.py
 APIDOC_EXCLUDES += */tests/* */migrations/* */wsgi.py */conftest.py
 APIDOC_EXCLUDES += deposit/settings/* web/settings/* dataset/*
 APIDOC_EXCLUDES += bin build dist utils node_modules
 APIDOC_SWH_EXCLUDES = $(patsubst %,"../%",$(APIDOC_EXCLUDES))
 
 html: sphinx/html
 help: sphinx/help
 
 # allow to skip apidoc generation, for modules where the overall documentation
 # structure, table of contents, etc., is manually curated
 ifeq ($(SKIP_APIDOC),yes)
 apidoc_dep =
 else
 apidoc_dep = apidoc-stamp
 endif
 
 sphinx/clean:
-	$(SPHINXBUILD) -M clean $(SPHINX_SRCDIR) $(SPHINX_BUILDDIR) $(SPHINX_OPTS)
+	$(SPHINXBUILD) -M clean $(SPHINX_SRCDIR) $(SPHINX_BUILDDIR) $(SPHINX_OPTS) $(SPHINXOPTS)
 sphinx/%: $(apidoc_dep)
-	$(SPHINXBUILD) -b $* $(SPHINX_SRCDIR) $(SPHINX_BUILDDIR)/$* $(SPHINX_OPTS)
+	$(SPHINXBUILD) -b $* $(SPHINX_SRCDIR) $(SPHINX_BUILDDIR)/$* $(SPHINX_OPTS) $(SPHINXOPTS)
 
 apidoc: $(apidoc_dep)
 apidoc-stamp:
 	$(SPHINXAPIDOC) $(APIDOC_OPTS) -o $(APIDOC_DIR) .. $(APIDOC_SWH_EXCLUDES)
 	# to silent Sphinx warnings about apidoc documents not included in any toctree
 	find $(shell pwd)/apidoc -name "*.rst" | xargs sed -i '1i:orphan:\n'
 	touch $@
 
 assets:
 
 .PHONY: clean clean-apidoc
 clean: sphinx/clean clean-apidoc
 clean-apidoc:
 	rm -rf $(APIDOC_DIR)
 	rm -f *-stamp
 
 
 # Local Variables:
 # mode: makefile
 # End: