Hung, J. T. (2016). More refinements of Hadamard Inequality [master's thesis, Tamkang University]. Airiti Library. https://www.airitilibrary.com/Article/Detail?DocID=U0002-1506201615341000
Wang, C. S. (1997). Note on Inequalities about Means. Tamsui Oxford Journal of Mathematical Sciences, (13), 57-64. https://doi.org/10.6988/TOJMS.199711.0057