diff --git a/src/TRGKit.jl b/src/TRGKit.jl
index 6b3ae25..34f7470 100644
--- a/src/TRGKit.jl
+++ b/src/TRGKit.jl
@@ -20,7 +20,7 @@ export run!
 
 # models
 include("models/ising.jl")
-export classical_ising, classical_ising_symmetric, Potts_βc, Ising_βc
+export classical_ising, classical_ising_symmetric, Potts_βc, Ising_βc, f_onsager
 
 include("models/gross-neveu.jl")
 export gross_neveu_start