diff --git a/doc/source/reference/kwant.builder.rst b/doc/source/reference/kwant.builder.rst
index c1aa98ebbac9d50ce41d2267d6e2ce9992fa3b9a..af02a1bc27e3bbeb3adc4f82e0594c7604b7ab07 100644
--- a/doc/source/reference/kwant.builder.rst
+++ b/doc/source/reference/kwant.builder.rst
@@ -15,6 +15,8 @@ Types
    BuilderLead
    SelfEnergyLead
    ModesLead
+   FiniteSystem
+   InfiniteSystem
 
 Abstract base classes
 ---------------------