Escobar Álvarez, M. A. (2011). English grammar and learning tasks for tourism studies. UNED - Universidad Nacional de Educación a Distancia.
Čikaški stil citiranja (17. izdanje)Escobar Álvarez, María Ángeles. English Grammar and Learning Tasks for Tourism Studies. Madrid: UNED - Universidad Nacional de Educación a Distancia, 2011.
MLA način citiranja (9. izdanje)Escobar Álvarez, María Ángeles. English Grammar and Learning Tasks for Tourism Studies. UNED - Universidad Nacional de Educación a Distancia, 2011.
Upozorenje: Ovi citati možda nisu uvijek 100% točni.