diff --git a/docs/_toc.yml b/docs/_toc.yml
index 684e7db9..cf549aa6 100644
--- a/docs/_toc.yml
+++ b/docs/_toc.yml
@@ -11,6 +11,7 @@ parts:
     chapters:
       - file: math/maxwell
         sections:
+        - file: math/maxwell_quantities
         - file: math/waveguide_port
         - file: math/overlap_integrals
       - file: math/thermal