[1]  Danielli D, Garofalo N,  Nhieu D. Notions of convexity in Carnot groups. Comm Analysis and Geometry, 2003, 11(2): 263--341

[2] Folland G B, Stein E M. Hardy Space on Homogeneous groups. Princeton, NJ: Princeton University Press, 1982

[3]  Gill P M, Pearce C E M,  Pe\v{c}ari\'{c} J. Hadamard's inequality for r-convex functions. J Math Anal Appl, 1997, 215: 461--470

[4]  Guo Baini, Qi Feng. Inequalities for generalized weighted mean values of convex function. Math Inequal Appl, 2001, 4: 195--202

[5]  Lu G Z, Manfredi J J, Stroffolini B. Convex functions on the Heisenberg group. Calc Var Partial Differential Equations, 2003, 19: 1--22

[6]  Pansu P. Mètriques de Carnot-Carathèodory et quasii-somètries des espacec symètriques de rang un. Ann Math, 1989, 129: 1--60

[7]  Pearce C E M, Pe\v{c}ari\'{c} J. A continuous analogue and an extension of Rad\'{o}'s formulae for convex and concave functions. Bull Austral Math  Soc, 1996, 53: 229--233

[8]  Pearce C E M, Pe\v{c}ari\'{c}  J,  \v{S}imi\'{c}  V. Stolarsky means and Hadamard's inequality. J Math Anal Appl, 1998, 220: 99--109

[9]  Qi Feng. Generalized weighted mean values with two parameters. Proceedings of the Royal Society of London Series A-Mathematics, Physical and Engineering Sciences, 1998, 454(1978): 2723--2732

[10] Stolarsky K B. Generalization of the logarithmic mean. Math Mag, 1975, 48: 87--92

[11] Sun Mingbao. Inequalities for two-parameter mean of convex function. Math Practice Theory (in Chinese), 1997, 27: 193--197

[12] Sun Mingbao, Yang Xiaoping. Inequalities of Hadamard type for r-convex functions in Carnot groups. Acta Math Appl Sin, 2004, 20(1): 123--132

[13] Uhrin B. Some remarks about the convolution of  unimodal functions. Ann Probab, 1984, 12: 640--645

[14] Yang G S,  HWang D Y. Refinements of Hadamaard's inequality for r-convex functions. Indian J Pure Appl Math, 2001, 32: 1571--1579