1. Andrews GE, Askey R, Roy R: Special Functions. Cambridge University Press, Cambridge; 1999.
2. Alsina C, Tomás MS: A geometrical proof of a new inequality for the gamma function. J. Inequal. Pure Appl. Math. 2005.,6(2): Article ID 48
3. Nguyen VV, Ngo PNN: An inequality for the gamma function. Int. Math. Forum 2009,4(28):1379–1382.
4. Díaz R, Pariguan E: On hypergeometric functions and Pochhammer k -symbol. Divulg. Mat. 2007,15(2):179–192.
5. Kokologiannaki CG, Krasniqi V: Some properties of the k -gamma function. Matematiche 2013,68(1):13–22.