Stoff, Sheldon Ptaschevitch, author
Harper & Row , 1969
Buku Teks
Marland, Sidney P., author
McGraw-Hill, 1974
Buku Teks
Department of Health, education and welfare, 1964
Buku Teks
Department of Health , 1977
Buku Teks
Noor, Abdun, author
World Bank, 1981
Buku Teks