Gaya APA
Happy, R, E.
(1991).
Sari Epidemiologi klinik
.
Yogyakarta:
Gadjah Mada University Press.
Gaya MLA
Happy, Ros, Endah.
"Sari Epidemiologi klinik".
Yogyakarta:
Gadjah Mada University Press,
1991.
Textbook.