“…Recently, non-Gaussianity of the primordial perturbation also has been studied by many authors [7,8,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48]. The main reason for non-Gaussianity to attract much attention is the expectation to future observations mentioned above.…”