Colin, Virginia L
McGraw-Hill , 1996
Buku Teks
Kelsen, Hans, author
University of California Press, 1957
Buku Teks
Husna Abbas, Nooral Zeila Junid, Khairiyah Abdul Muttalib, Rohana Mohd Johari
Ministry of Health, 2001
Buku Referensi
Kottak, Conrad Phillip, author
McGraw-Hill, 2012
Buku Teks
Sheldon, Sidney, author
Gramedia Pustaka Utama , 1993
Buku Teks