Julio Enrique Duarte, M. A. A. V. (2011). Utilization of didactic material for teaching science and technology concepts in children. Universidad Pedagógica y Tecnológica de Colombia.
Lua i Stíl Chicago (17ú heag.)Julio Enrique Duarte, Maria Aidé Angarita Velandia. Utilization of Didactic Material for Teaching Science and Technology Concepts in Children. Universidad Pedagógica y Tecnológica de Colombia, 2011.
Lua MLA (9ú heag.)Julio Enrique Duarte, Maria Aidé Angarita Velandia. Utilization of Didactic Material for Teaching Science and Technology Concepts in Children. Universidad Pedagógica y Tecnológica de Colombia, 2011.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.