diff --git a/Nevanlinna/firstMain.lean b/Nevanlinna/firstMain.lean
index 5e30048..b3a912e 100644
--- a/Nevanlinna/firstMain.lean
+++ b/Nevanlinna/firstMain.lean
@@ -227,4 +227,6 @@ theorem Nevanlinna_firstMain₂
   (h₁f : MeromorphicOn f ⊤) :
   |(h₁f.T_infty r) - ((h₁f.sub (MeromorphicOn.const a)).T_infty r)| ≤ logpos ‖a‖ + log 2 := by
 
+  -- See Lang, p. 168
+
   sorry