diff --git a/requirements.txt b/requirements.txt
--- a/requirements.txt
+++ b/requirements.txt
@@ -33,3 +33,4 @@ typing==3.6.1
 watchdog==0.8.3
 web.py==0.38
 webcolors==1.7
+https://projects.bigasterisk.com/rdfdb/rdfdb-0.3.0.tar.gz