diff --git a/unsupported/Eigen/src/BVH/BVAlgorithms.h b/unsupported/Eigen/src/BVH/BVAlgorithms.h
index 6372576..4032029 100644
--- a/unsupported/Eigen/src/BVH/BVAlgorithms.h
+++ b/unsupported/Eigen/src/BVH/BVAlgorithms.h
@@ -86,9 +86,11 @@
   bool intersectObject(const Object2 &obj) { return intersector.intersectObjectObject(stored, obj); }
   Object1 stored;
   Intersector &intersector;
+private:
+  ei_intersector_helper2& operator=(const ei_intersector_helper2&);
 };
 
-/**  Given two BVH's, runs the query on their cartesian product encapsulated by \a intersector.
+/**  Given two BVH's, runs the query on their Cartesian product encapsulated by \a intersector.
   *  The Intersector type must provide the following members: \code
      bool intersectVolumeVolume(const BVH1::Volume &v1, const BVH2::Volume &v2) //returns true if product of volumes intersects the query
      bool intersectVolumeObject(const BVH1::Volume &v1, const BVH2::Object &o2) //returns true if the volume-object product intersects the query
@@ -207,6 +209,8 @@
   Scalar minimumOnObject(const Object1 &obj) { return minimizer.minimumOnObjectObject(obj, stored); }
   Object2 stored;
   Minimizer &minimizer;
+private:
+  ei_minimizer_helper1& operator=(const ei_minimizer_helper1&) {}
 };
 
 template<typename Volume2, typename Object2, typename Object1, typename Minimizer>
diff --git a/unsupported/Eigen/src/NonLinearOptimization/HybridNonLinearSolver.h b/unsupported/Eigen/src/NonLinearOptimization/HybridNonLinearSolver.h
index aba31b2..0ef3eca 100644
--- a/unsupported/Eigen/src/NonLinearOptimization/HybridNonLinearSolver.h
+++ b/unsupported/Eigen/src/NonLinearOptimization/HybridNonLinearSolver.h
@@ -124,6 +124,8 @@
     Index ncfail;
     Scalar actred, prered;
     FVectorType wa1, wa2, wa3, wa4;
+
+    HybridNonLinearSolver& operator=(const HybridNonLinearSolver&);
 };
 
 
diff --git a/unsupported/Eigen/src/NonLinearOptimization/LevenbergMarquardt.h b/unsupported/Eigen/src/NonLinearOptimization/LevenbergMarquardt.h
index 63eb667..a8f3f3e 100644
--- a/unsupported/Eigen/src/NonLinearOptimization/LevenbergMarquardt.h
+++ b/unsupported/Eigen/src/NonLinearOptimization/LevenbergMarquardt.h
@@ -133,6 +133,8 @@
     Scalar delta;
     Scalar ratio;
     Scalar pnorm, xnorm, fnorm1, actred, dirder, prered;
+
+    LevenbergMarquardt& operator=(const LevenbergMarquardt&);
 };
 
 template<typename FunctorType, typename Scalar>
diff --git a/unsupported/Eigen/src/NumericalDiff/NumericalDiff.h b/unsupported/Eigen/src/NumericalDiff/NumericalDiff.h
index 8d23cb4..a25c9cd 100644
--- a/unsupported/Eigen/src/NumericalDiff/NumericalDiff.h
+++ b/unsupported/Eigen/src/NumericalDiff/NumericalDiff.h
@@ -130,6 +130,8 @@
     }
 private:
     Scalar epsfcn;
+
+    NumericalDiff& operator=(const NumericalDiff&);
 };
 
 //vim: ai ts=4 sts=4 et sw=4