Gaya APA
DAHLAN, M, S.
(2014).
Menelaah validitas penelitian observasisional
.
Jakarta:
Sagung Seto.
Gaya MLA
DAHLAN, M., Sopiyudin.
"Menelaah validitas penelitian observasisional".
Jakarta:
Sagung Seto,
2014.
Printed Book.