Gaya APA
Simatupang, L., Shombing, L. (2017).
Issues in Research and Their International Publication .
Tarutung:
STAKPN Tarutung Press.
Gaya MLA
Simatupang, Limmarten., Shombing, Lince.
"Issues in Research and Their International Publication".
Tarutung:
STAKPN Tarutung Press,
2017.
Text.