Horath, Larry
Prentice-Hall, 2001
Buku Teks
edited by Douglas L. Moeller, James L. Moeller
Wolters Kluwer, 2007
Buku Teks
Fakultas Ilmu kesehatan Masyarakat Universitas Indonesia, 2010
Artikel Jurnal
Nagarsheth, Nimesh
Jones and Bartlett Publishers, 2010
Buku Teks
Ehrenpreis, Seymour
McGraw-Hill, 2001
Buku Referensi