Gaya APA

Ajam, M, R., Usman, A, H. (2009). Practical English For Economic Students Part One (Cet.1). : surya sarana grafika.

Gaya MLA

Ajam, M., Ridha., Usman, Abdurrrahman, Hi. "Practical English For Economic Students Part One". Cet.1 : surya sarana grafika, 2009. Buku.