Biddle, S.,Goudas, M.(1996).Analysis of children's physical activity and its association with adult encouragement and social cognitive variables.Journal of School Health.66(2),75-78.
Brown, B. A.,Frankel, B. G.,Fennell, M. P.(1989).Hugs or shrugs: Parental and peer influence on continuity of involvement in sport by female and adolescents.Sex Roles.20,397-409.