diff --git a/include/teqp/models/eos.hpp b/include/teqp/models/eos.hpp
index dd8e17dda7c812ccecd1e41c8f326bcdcc4a2339..154bdfc9b429eb5eb6ea2554a058f3b5ff9f0ad2 100644
--- a/include/teqp/models/eos.hpp
+++ b/include/teqp/models/eos.hpp
@@ -2,6 +2,7 @@
 
 #include <optional>
 #include "teqp/constants.hpp"
+#include "teqp/types.hpp"
 
 /** 
 To add: