Gaya APA
Pennak, R, W. (1978).
Fresh-Water Invertebrates of the United States Second Edition .
New York:
A Wiley-Interscience Publication.
Gaya MLA
Pennak, Robert, W..
"Fresh-Water Invertebrates of the United States Second Edition".
New York:
A Wiley-Interscience Publication,
1978.
Text.