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