2Dit~nan JM. Personality structure: Emergency of the five-factor mode[ J]. Annual Review of Psychology, 1990, (41) :417-440.
3Watkins PC, Seheer J, Ovnieek M, &Kolts R L. The debt of grati- tude:Dissociating gratitude and in debtedness [ J ]. Cognition and Emotion ,2006, (20) :217-241.