Gaya APA
Pontius, F, W. (1990).
water quality and treatment; a handbook of community water supplies (4).
new york:
Mc Graw-Hill.
Gaya MLA
Pontius, Frederick, W..
"water quality and treatment; a handbook of community water supplies".
4
new york:
Mc Graw-Hill,
1990.
Kesehatan Masyarakat.