A note on the Neuman-S\'andor Mean
  In this article, we present the best possible upper and lower bounds for the Neuman-S\'andor mean in terms of the geometric combinations of harmonic and quadratic means, geometric and quadratic means, harmonic and contra-harmonic means, and geometric and contra-harmonic means. 
Tie-Hong Zhao, Yu-Ming Chu and Bao-Yu Liu
math.CA