Gaya APA
Sumardi, ., Widyastuti, S. (2007).
Dasar-Dasar Perlindungan Hutan (Cet. 2).
Bulaksumur, Yogyakarta:
Gadjah Mada University Press.
Gaya MLA
Sumardi, ., Widyastuti, S.M..
"Dasar-Dasar Perlindungan Hutan".
Cet. 2
Bulaksumur, Yogyakarta:
Gadjah Mada University Press,
2007.
TEXT BOOK.