diff --git a/common-defs.tex b/common-defs.tex
index 85229bc..33c3b5a 100644
--- a/common-defs.tex
+++ b/common-defs.tex
@@ -134,15 +134,21 @@
     Image source: #1, #2 (\underline{\href{#4}{link}}). %
     Licensed #3.}
 
+\DeclareRefcontext{webref}{labelprefix=W}
+\DeclareRefcontext{patref}{labelprefix=P}
+\DeclareRefcontext{defref}{}
+
 \newcommand{\chapterbibliography}{
     \clearpage % clearpage flushes all figures. force this here so we don't get figures floating in between references.
-    \newrefcontext[labelprefix=W]
+    \newrefcontext{webref}
     \printbibliography[type={online},title={Web sources},resetnumbers,heading=subbibintoc]
-    \newrefcontext
+    \newrefcontext{defref}
     \printbibliography[nottype={online},nottype={patent},resetnumbers,heading=subbibintoc]
-    \newrefcontext[labelprefix=P]
+    \newrefcontext{patref}
     \printbibliography[type={patent},title={Patent References},resetnumbers,heading=subbibintoc]
 }
 
+\newrefcontext{defref}
+
 \hyphenation{a-me-na-ble}