Gaya APA
Purba, Y, S. (2024).
Speaking English in Professional Situations (Cetakan Pertama).
Sleman, Yogyakarta:
Terang Sejati.
Gaya MLA
Purba, Y., Sanaha.
"Speaking English in Professional Situations".
Cetakan Pertama
Sleman, Yogyakarta:
Terang Sejati,
2024.
.