diff --git a/cosets/src/util/coxeter.hpp b/cosets/src/util/coxeter.hpp
index d9e49c8..054a49f 100644
--- a/cosets/src/util/coxeter.hpp
+++ b/cosets/src/util/coxeter.hpp
@@ -1,3 +1,5 @@
+#pragma once
+
 #include <iostream>
 #include <vector>
 #include <iomanip>
diff --git a/cosets/src/util/mirrors.hpp b/cosets/src/util/mirrors.hpp
index fc18e37..6a629bd 100644
--- a/cosets/src/util/mirrors.hpp
+++ b/cosets/src/util/mirrors.hpp
@@ -1,3 +1,5 @@
+#pragma once
+
 #include <cmath>
 #include <vector>
 #include <iostream>