1. M. Abramowitz, I.A. Stegun (Eds.), Handbook of Mathematical Functions with Formulas and Mathematical Tables, Dover, New York, 1965.
2. Sharp bounds for the ratio of q-gamma functions;Alzer;Math. Nachr.,2001
3. Sharp inequalities for the digamma and polygamma functions;Alzer;Forum Math.,2004
4. The q-gamma and q-beta functions;Askey;Appl. Anal.,1978
5. N. Batir, An interesting double inequality for Euler's gamma function, J. Inequal. Pure Appl. Math. 5(4) article 97 (2004) 〈http://jipam.vu.edu.au/〉.