Dillström Norgen, V. (1985). The development of the semiotic function: Studies of children's graphic and verbal representations. Uppsala Universitet ; Distributor, Almqvist & Wiksell International.
Lua i Stíl Chicago (17ú heag.)Dillström Norgen, Valborg. The Development of the Semiotic Function: Studies of Children's Graphic and Verbal Representations. Uppsala : Stockholm, Sweden: Uppsala Universitet ; Distributor, Almqvist & Wiksell International, 1985.
Lua MLA (8ú heag.)Dillström Norgen, Valborg. The Development of the Semiotic Function: Studies of Children's Graphic and Verbal Representations. Uppsala Universitet ; Distributor, Almqvist & Wiksell International, 1985.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.