{\it a_{11}}\,{\it a_{22}}\,{\it a_{33}}-{\it a_{12}}\,{\it a_{21}}
 \,{\it a_{33}}-{\it a_{11}}\,{\it a_{23}}\,{\it a_{32}}+{\it a_{13}}
 \,{\it a_{21}}\,{\it a_{32}}+{\it a_{12}}\,{\it a_{23}}\,
 {\it a_{31}}-{\it a_{13}}\,{\it a_{22}}\,{\it a_{31}}