diff --git a/COPYING b/COPYING
index 88798ab..caeca07 120000
--- a/COPYING
+++ b/COPYING
@@ -1 +1 @@
-/usr/share/automake-1.15/COPYING
\ No newline at end of file
+/usr/share/automake-1.14/COPYING
\ No newline at end of file
diff --git a/INSTALL b/INSTALL
index ddcdb76..f812f5a 120000
--- a/INSTALL
+++ b/INSTALL
@@ -1 +1 @@
-/usr/share/automake-1.15/INSTALL
\ No newline at end of file
+/usr/share/automake-1.14/INSTALL
\ No newline at end of file
diff --git a/ax_init_standard_project.m4 b/ax_init_standard_project.m4
index b5840d7..4128d9f 100644
--- a/ax_init_standard_project.m4
+++ b/ax_init_standard_project.m4
@@ -273,7 +273,7 @@ EOF
 AC_DEFUN([AX_USE_CXX], [
   m4_include(ax_cxx_compile_stdcxx_11.m4)
   AC_LANG(C++)
-  AX_CXX_COMPILE_STDCXX_14(noext, optional)
+  AX_CXX_COMPILE_STDCXX_11(noext, optional)
   AC_PROG_CXX
   AC_PROG_CPP
 
diff --git a/configure.ac b/configure.ac
index da95cdd..318ac2b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -32,7 +32,7 @@ AX_BUILD_EXAMPLES
 #AX_CHECK_QT([QT], [QtCore QtGui QtNetwork], [QtWidgets])
 #AX_REQUIRE_QT([QT], [QtCore QtGui QtNetwork], [QtWidgets])
 #AX_QT_NO_KEYWORDS
-AX_REQUIRE_STDCXX_14
+AX_REQUIRE_STDCXX_11
 
 # create output
 AC_OUTPUT
diff --git a/src/matrix.hxx b/src/matrix.hxx
index 26e4ee4..c4e20e8 100644
--- a/src/matrix.hxx
+++ b/src/matrix.hxx
@@ -10,15 +10,15 @@
 #include <cassert>
 #include <type_traits>
 
-template<typename TYPE, size_t TROWS=0, size_t TCOLUMNS=0> class Matrix {
-
-    //........................................................const.variables
+template<typename TYPE, typename ARRAY=TYPE*> class MatrixBase {
+    
+    //..............................................................constants
   public:
 
-    static const size_t ROWS = TROWS;
-    static const size_t COLUMNS = TCOLUMNS;
-    static const size_t SIZE = ROWS*COLUMNS;
-    static const size_t MEM_SIZE = ROWS*COLUMNS*sizeof(TYPE);
+    const size_t ROWS;
+    const size_t COLUMNS;
+    const size_t SIZE;
+    const size_t MEM_SIZE;
 
     //...............................................................typedefs
   public: 
@@ -36,12 +36,14 @@ template<typename TYPE, size_t TROWS=0, size_t TCOLUMNS=0> class Matrix {
     class RowVector {
       public:
         TYPE& operator[](size_t column) {
+          assert(column<_m.COLUMNS);
           return _v[column];
         }
       protected:
-        friend class Matrix;
+        friend class MatrixBase;
         RowVector() = delete; // forbidden
-        RowVector(TYPE c[COLUMNS]): _v(c) {}
+        RowVector(const MatrixBase& m, TYPE c[]): _m(m), _v(c) {}
+        const MatrixBase& _m;
         TYPE *_v;
     };
 
@@ -49,12 +51,14 @@ template<typename TYPE, size_t TROWS=0, size_t TCOLUMNS=0> class Matrix {
     class ConstRowVector {
       public:
         const TYPE& operator[](size_t column) const {
+          assert(column<_m.COLUMNS);
           return _v[column];
         }
       protected:
-        friend class Matrix;
+        friend class MatrixBase;
         ConstRowVector() = delete; // forbidden
-        ConstRowVector(const TYPE c[COLUMNS]): _v(c) {}
+        ConstRowVector(const MatrixBase& m, const TYPE c[]): _m(m), _v(c) {}
+        const MatrixBase& _m;
         const TYPE *_v;
     };
     
@@ -66,17 +70,16 @@ template<typename TYPE, size_t TROWS=0, size_t TCOLUMNS=0> class Matrix {
     /// @name construction
     ///{
     
-    Matrix() {
-      memset(_c, 0, MEM_SIZE);
+    MatrixBase(size_t rows, size_t columns):
+        ROWS(rows), COLUMNS(columns),
+        SIZE(ROWS*COLUMNS), MEM_SIZE(SIZE*sizeof(TYPE)) {
     }
-    
+
     template<typename ...ARGS>
-        Matrix(ARGS...t): _c{std::forward<TYPE>(t)...} {
-      static_assert(sizeof...(t)==SIZE, "variadic matrix initialisation requires correct array size");
-    }
-    
-    Matrix(const Matrix& o) {
-      memcpy(_c, o._c, MEM_SIZE);
+        MatrixBase(size_t rows, size_t columns, ARGS...t):
+            ROWS(rows), COLUMNS(columns),
+            SIZE(ROWS*COLUMNS), MEM_SIZE(SIZE*sizeof(TYPE)),
+            _c{std::forward<TYPE>(t)...} {
     }
 
     ///}
@@ -84,47 +87,38 @@ template<typename TYPE, size_t TROWS=0, size_t TCOLUMNS=0> class Matrix {
     /// @name operators
     ///{
     
-    Matrix& operator=(TYPE oc[ROWS][COLUMNS]) {
+    MatrixBase& operator=(TYPE oc[]) {
+      assert(sizeof(oc)==MEM_SIZE);
       memcpy(_c, oc, MEM_SIZE);
       return *this;
     }
     
-    Matrix& operator=(const Matrix& o) {
+    MatrixBase& operator=(const MatrixBase& o) {
+      assert_check(o);
       memcpy(_c, o._c, MEM_SIZE);
       return *this;
     }
-    
-    bool operator==(const Matrix& o) const {
+
+    bool operator==(const MatrixBase& o) const {
+      if (!check(o)) return false;
       TYPE *to((TYPE*)(_c)+SIZE), *from((TYPE*)(o._c)+SIZE);
       while (to>(TYPE*)(_c)) if (*--to != *--from) return false;
       return true;
     }
 
-    bool operator!=(const Matrix& o) const {
+    bool operator!=(const MatrixBase& o) const {
       return !operator==(o);
     }
 
-    Matrix<TYPE, COLUMNS, ROWS> T() const {
-      Matrix<TYPE, COLUMNS, ROWS> res;
-      for (size_t row(0); row<ROWS; ++row)
-        for (size_t column(0); column<COLUMNS; ++column)
-          res(column, row) = operator()(row, column);
-      return res;
-    }
-    
-    Matrix operator-() const {
-      Matrix res;
-      for (TYPE *to((TYPE*)(res._c)+SIZE); to>(TYPE*)(_c); --to) *to = -*to;
-      return res;
-    }
-
-    Matrix& operator+=(const Matrix& o) {
+    MatrixBase& operator+=(const MatrixBase& o) {
+      assert_check(o);
       TYPE *to((TYPE*)(_c)+SIZE), *from((TYPE*)(o._c)+SIZE);
       while (to>(TYPE*)(_c)) *--to += *--from;
       return *this;
     }
 
-    Matrix& operator-=(const Matrix& o) {
+    MatrixBase& operator-=(const MatrixBase& o) {
+      assert_check(o);
       TYPE *to((TYPE*)(_c)+SIZE), *from((TYPE*)(o._c)+SIZE);
       while (to>(TYPE*)(_c)) *--to -= *--from;
       return *this;
@@ -134,116 +128,131 @@ template<typename TYPE, size_t TROWS=0, size_t TCOLUMNS=0> class Matrix {
 
     /// @name element access
     ///{
-
+    
     TYPE& operator()(size_t row, size_t column) {
       assert(row<ROWS);
       assert(column<COLUMNS);
-      return _c[row][column];
+      return *((TYPE*)_c+row*COLUMNS+column);
     }
     
     const TYPE& operator()(size_t row, size_t column) const {
       assert(row<ROWS);
       assert(column<COLUMNS);
-      return _c[row][column];
+      return *((TYPE*)_c+row*COLUMNS+column);
     }
     
     RowVector operator[](size_t row) {
       assert(row<ROWS);
-      return RowVector(_c[row]);
+      return RowVector(*this, (TYPE*)_c+row*COLUMNS);
     }
     
     const ConstRowVector operator[](size_t row) const {
       assert(row<ROWS);
-      return ConstRowVector(_c[row]);
+      return ConstRowVector(*this, (TYPE*)_c+row*COLUMNS);
     }
     
     ///}
 
+    //................................................................methods
+  protected:
+
+    virtual void assert_check(const MatrixBase& o) const {}
+    virtual bool check(const MatrixBase& o) const {
+      return true;
+    }
+
     //..............................................................variables
   protected:
     
-    TYPE _c[ROWS][COLUMNS];
-    
-};
+    ARRAY _c;
 
-template<typename TYPE> class Matrix<TYPE, 0, 0> {
+};
 
-    //..............................................................constants
-  public:
+//==============================================================================
 
-    const size_t ROWS;
-    const size_t COLUMNS;
-    const size_t SIZE;
-    const size_t MEM_SIZE;
+template<typename TYPE, size_t TROWS=0, size_t TCOLUMNS=0> class Matrix:
+  public MatrixBase<TYPE, TYPE[TROWS][TCOLUMNS]> {
 
     //...............................................................typedefs
-  public: 
+  private:
 
-    /// @name Auxiliary Classes
+    typedef MatrixBase<TYPE, TYPE[TROWS][TCOLUMNS]> Parent;
+
+    //................................................................methods
+  public:
+
+    /// @name construction
     ///{
+    
+    Matrix(): Parent(TROWS, TCOLUMNS) {}
+    
+    template<typename ...ARGS>
+        Matrix(ARGS...t): Parent(TROWS, TCOLUMNS, t...) {
+      static_assert(sizeof...(t)==TROWS*TCOLUMNS,
+                    "wrong array size");
+    }
 
-    /// Return One Row as Vector, internally used for element access
-    /** Only used to access values:
+    Matrix(const Matrix& o): Matrix() {
+      memcpy(Parent::_c, o._c, Parent::MEM_SIZE);
+    }
 
-        @code
-        Matrix<int,4,4> m;
-        m[2][2] = 1;
-        @endcode */
-    class RowVector {
-      public:
-        TYPE& operator[](size_t column) {
-          assert(column<_m.COLUMNS);
-          return _v[column];
-        }
-      protected:
-        friend class Matrix;
-        RowVector() = delete; // forbidden
-        RowVector(const Matrix& m, TYPE c[]): _m(m), _v(c) {}
-        const Matrix& _m;
-        TYPE *_v;
-    };
+    ///}
 
-    /// Same as RowVector, but in a constant environment.
-    class ConstRowVector {
-      public:
-        const TYPE& operator[](size_t column) const {
-          assert(column<_m.COLUMNS);
-          return _v[column];
-        }
-      protected:
-        friend class Matrix;
-        ConstRowVector() = delete; // forbidden
-        ConstRowVector(const Matrix& m, const TYPE c[]): _m(m), _v(c) {}
-        const Matrix& _m;
-        const TYPE *_v;
-    };
+    /// @name operators
+    ///{
     
-    ///}
+    Matrix& operator=(TYPE oc[TROWS][TCOLUMNS]) {
+      memcpy(Parent::_c, oc, Parent::MEM_SIZE);
+      return *this;
+    }
+    
+    Matrix<TYPE, TCOLUMNS, TROWS> T() const {
+      Matrix<TYPE, TCOLUMNS, TROWS> res;
+      for (size_t row(0); row<TROWS; ++row)
+        for (size_t column(0); column<TCOLUMNS; ++column)
+          res(column, row) = Parent::operator()(row, column);
+      return res;
+    }
+    
+    Matrix operator-() const {
+      Matrix res;
+      for (TYPE *to((TYPE*)(res._c)+Parent::SIZE); to>(TYPE*)(Parent::_c); --to)
+        *to = -*to;
+      return res;
+    }
+
+};
+
+//==============================================================================
+
+template<typename TYPE> class Matrix<TYPE, 0, 0>: public MatrixBase<TYPE> {
+
+    //...............................................................typedefs
+  private:
+
+    typedef MatrixBase<TYPE> Parent;
 
     //................................................................methods
   public:
-
+    
     /// @name construction
     ///{
     
     Matrix(size_t rows, size_t columns):
-        ROWS(rows),
-        COLUMNS(columns),
-        SIZE(rows*columns),
-        MEM_SIZE(rows*columns*sizeof(TYPE)),
-        _c(new TYPE[rows*columns]) {
-      memset(_c, 0, MEM_SIZE);
+        Parent(rows, columns) {
+      Parent::_c = new TYPE[rows*columns];
+      memset(Parent::_c, 0, Parent::MEM_SIZE);
     }
     
     template<typename ...ARGS>
         Matrix(size_t rows, size_t columns, ARGS...t):
             Matrix(rows, columns) {
-      assert(sizeof...(t)==SIZE);
-      copy_args(_c, t...);
+      assert(sizeof...(t)==Parent::SIZE);
+      copy_args(Parent::_c, t...);
     }
 
-    Matrix(const Matrix& o): Matrix(o.ROWS, o.COLUMNS) {
-      memcpy(_c, o._c, MEM_SIZE);
+    Matrix(const Matrix& o): Matrix(o.ROWS, o.Parent::COLUMNS) {
+      memcpy(Parent::_c, o.Parent::_c, Parent::MEM_SIZE);
     }
 
     ///}
@@ -251,107 +260,56 @@ template<typename TYPE> class Matrix<TYPE, 0, 0> {
     /// @name destruction
     ///{
 
-    ~Matrix() {
-      delete[] _c;
+    virtual ~Matrix() {
+      delete[] Parent::_c;
     }
     
     ///}
-
+    
     /// @name operators
     ///{
-    
-    Matrix& operator=(TYPE oc[]) {
-      assert(sizeof(oc)==MEM_SIZE);
-      memcpy(_c, oc, MEM_SIZE);
-      return *this;
-    }
-    
+
     Matrix& operator=(const Matrix& o) {
-      if (o.ROWS!=ROWS&&o.COLUMNS!=COLUMNS) {
-        delete[] _c;
-        ROWS = o.ROWS;
-        COLUMNS = o.COLUMNS;
-        SIZE = o.SIZE;
-        MEM_SIZE = o.MEM_SIZE;
-        _c = new TYPE[SIZE];
+      if (o.ROWS!=Parent::ROWS&&o.COLUMNS!=Parent::COLUMNS) {
+        delete[] Parent::_c;
+        Parent::ROWS = o.ROWS;
+        Parent::COLUMNS = o.COLUMNS;
+        Parent::SIZE = o.SIZE;
+        Parent::MEM_SIZE = o.MEM_SIZE;
+        Parent::_c = new TYPE[Parent::SIZE];
       }
-      memcpy(_c, o._c, MEM_SIZE);
-      return *this;
-    }
-
-    bool operator==(const Matrix& o) const {
-      if (o.ROWS!=ROWS||o.COLUMNS!=COLUMNS) return false;
-      TYPE *to((TYPE*)(_c)+SIZE), *from((TYPE*)(o._c)+SIZE);
-      while (to>(TYPE*)(_c)) if (*--to != *--from) return false;
-      return true;
-    }
-
-    bool operator!=(const Matrix& o) const {
-      return !operator==(o);
+      return Parent::operator=(o);
     }
 
     Matrix T() const {
-      Matrix res(COLUMNS, ROWS);
-      for (size_t row(0); row<ROWS; ++row)
-        for (size_t column(0); column<COLUMNS; ++column)
-          res(column, row) = operator()(row, column);
+      Matrix res(Parent::COLUMNS, Parent::ROWS);
+      for (size_t row(0); row<Parent::ROWS; ++row)
+        for (size_t column(0); column<Parent::COLUMNS; ++column)
+          res(column, row) = Parent::operator()(row, column);
       return res;
     }
 
     Matrix operator-() const {
-      Matrix res(COLUMNS, ROWS);
-      for (TYPE *to((TYPE*)(res._c)+SIZE); to>(TYPE*)(_c); --to) *to = -*to;
+      Matrix res(Parent::COLUMNS, Parent::ROWS);
+      for (TYPE *to((TYPE*)(res._c)+Parent::SIZE); to>(TYPE*)(Parent::_c); --to)
+        *to = -*to;
       return res;
     }
 
-    Matrix& operator+=(const Matrix& o) {
-      assert(o.ROWS==ROWS);
-      assert(o.COLUMNS==COLUMNS);
-      TYPE *to((TYPE*)(_c)+SIZE), *from((TYPE*)(o._c)+SIZE);
-      while (to>(TYPE*)(_c)) *--to += *--from;
-      return *this;
-    }
-
-    Matrix& operator-=(const Matrix& o) {
-      assert(o.ROWS==ROWS);
-      assert(o.COLUMNS==COLUMNS);
-      TYPE *to((TYPE*)(_c)+SIZE), *from((TYPE*)(o._c)+SIZE);
-      while (to>(TYPE*)(_c)) *--to -= *--from;
-      return *this;
-    }
-
-    ///}
-
-    /// @name element access
-    ///{
-    
-    TYPE& operator()(size_t row, size_t column) {
-      assert(row<ROWS);
-      assert(column<COLUMNS);
-      return *(_c+row*COLUMNS+column);
-    }
-    
-    const TYPE& operator()(size_t row, size_t column) const {
-      assert(row<ROWS);
-      assert(column<COLUMNS);
-      return *(_c+row*COLUMNS+column);
-    }
-    
-    RowVector operator[](size_t row) {
-      assert(row<ROWS);
-      return RowVector(*this, _c+row*COLUMNS);
-    }
-    
-    const ConstRowVector operator[](size_t row) const {
-      assert(row<ROWS);
-      return ConstRowVector(*this, _c+row*COLUMNS);
-    }
-    
     ///}
 
     //................................................................methods
   protected:
 
+    virtual void assert_check(const Matrix& o) const {
+      assert(o.ROWS==Parent::ROWS);
+      assert(o.COLUMNS==Parent::COLUMNS);
+    }
+
+    virtual bool check(const Matrix& o) const {
+      return o.ROWS==Parent::ROWS && o.COLUMNS==Parent::COLUMNS;
+    }
+
     void copy_args(TYPE*) {}
     template<typename ...ARGS>
         void copy_args(TYPE* to, TYPE t1, ARGS...t) {
@@ -359,13 +317,10 @@ template<typename TYPE> class Matrix<TYPE, 0, 0> {
       copy_args(++to, t...);
     }
 
-    //..............................................................variables
-  protected:
-    
-    TYPE* _c;
-    
 };
 
+//==============================================================================
+
 template<typename TYPE, size_t ROWS, size_t COLUMNS>
     Matrix<TYPE, ROWS, COLUMNS> operator+(const Matrix<TYPE, ROWS, COLUMNS>& m1, const Matrix<TYPE, ROWS, COLUMNS>& m2) {
   Matrix<TYPE, ROWS, COLUMNS> res(m1);
diff --git a/test/basic.cxx b/test/basic.cxx
index 7e29e7f..fce9437 100644
--- a/test/basic.cxx
+++ b/test/basic.cxx
@@ -105,13 +105,6 @@ class TemplateMatrixTest: public CppUnit::TestFixture {
                        5, 6, 7, 9);
       Matrix<T,2,4> m4(9, 2, 3, 4,
                        5, 6, 7, 8);
-      std::cout<<std::endl
-               <<"m1 = "<<std::endl
-               <<m1<<std::endl
-               <<"m2 = "<<std::endl
-               <<m2<<std::endl
-               <<"m3 = "<<std::endl
-               <<m3<<std::endl;
       CPPUNIT_ASSERT(m1==m2);
       CPPUNIT_ASSERT(m1!=m3);
       CPPUNIT_ASSERT(m1!=m4);