- Feng Qi, Ravi P. Agarwal, “On complete monotonicity for several classes of functions related to ratios of gamma functions”, J Inequal Appl, 2019, no. 1, 2019, 36
- Feng Qi, Cristinel Mortici, “Some inequalities for the trigamma function in terms of the digamma function”, Applied Mathematics and Computation, 271, 2015,
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