Richard, J., C. (2013). English 1: conversation program, taken from interchange 3rd edition, book 1 (ed. 3rd). (4) Organisasi Perusahaan: Teo: .

Richard, J., C.. English 1: conversation program, taken from interchange 3rd edition, book 1. ed. 3rd (4) Organisasi Perusahaan: Teo: , 2013. Text.