Stewart, Rosemary, author
Prentice-Hall, 1982
Buku Teks
United Nations Population Fund
UNFPA, 1994
Buku Teks
Stewart, Rosemary, author
Prentice-Hall, 1982
Buku Teks
The American Water Works Association, Inc.
McGraw-Hill, 1971
Buku Referensi
Azhar Kasim, author
2011
Artikel Jurnal