diff --git a/tsp/calc_lkh_alpha.hpp b/tsp/calc_lkh_alpha.hpp
index 30bb96b0..d0c111b8 100644
--- a/tsp/calc_lkh_alpha.hpp
+++ b/tsp/calc_lkh_alpha.hpp
@@ -2,6 +2,8 @@
 
 #include <vector>
 
+#include "tsp/mst_edges.hpp"
+
 // http://webhotel4.ruc.dk/~keld/research/LKH/LKH-2.0/DOC/LKH_REPORT.pdf, p.20
 template <class DistanceMatrix> auto calc_lkh_alpha(const DistanceMatrix &dist) {
     using T = decltype((*dist.adjacents(0).begin()).second);
diff --git a/tsp/csr_distance_matrix.hpp b/tsp/csr_distance_matrix.hpp
index 871bdd67..609cb2bb 100644
--- a/tsp/csr_distance_matrix.hpp
+++ b/tsp/csr_distance_matrix.hpp
@@ -4,6 +4,8 @@
 #include <utility>
 #include <vector>
 
+#include "tsp/calc_lkh_alpha.hpp"
+
 template <class T> class csr_distance_matrix {
 
     int _rows = 0;
diff --git a/tsp/held_karp.hpp b/tsp/held_karp.hpp
index 2d780f2e..8a5c5653 100644
--- a/tsp/held_karp.hpp
+++ b/tsp/held_karp.hpp
@@ -1,7 +1,7 @@
 #pragma once
 
-#include "csr_distance_matrix.hpp"
-#include "minimum_one_tree.hpp"
+#include "tsp/csr_distance_matrix.hpp"
+#include "tsp/minimum_one_tree.hpp"
 
 #include <algorithm>
 #include <utility>