Citazione APA

Hughes, J., & Stephenson, H. (2015). Life A1-A2: Student's book with online workbook. Singapore: National Geographic Learning.

Stile di citazione Chicago

Hughes, John, e Helen Stephenson. Life A1-A2: Student's Book With Online Workbook. Singapore: National Geographic Learning, 2015.

Citazione MLA

Hughes, John, e Helen Stephenson. Life A1-A2: Student's Book With Online Workbook. Singapore: National Geographic Learning, 2015.

Attenzione: Queste citazioni potrebbero non essere precise al 100%.