Subharmonicity of the modulus of quasiregular harmonic mappings
  In this note we determine all numbers $q\in \mathbf R$ such that $|u|^q$ is a subharmonic function, provided that $u$ is a $K-$quasiregular harmonic mappings in an open subset $\Omega$ of the Euclidean space $\mathbf R^n$. 
David Kalaj and Vesna Manojlovi\'c
math.FA