On Povzner--Wienholtz-type Self-Adjointness Results for Matrix-Valued   Sturm--Liouville Operators
  We derive Povzner--Wienholtz-type self-adjointness results for $m\times m$ matrix-valued Sturm--Liouville operators $T=R^{-1}\big[-\f{d}{dx}P\f{d}{dx}+Q\big]$ in $L^2((a,b);Rdx)^m$, $m\in\bbN$, for $(a,b)$ a half-line or $\bbR$. 
Steve Clark and Fritz Gesztesy