Pauker, Guy J., author
McGraw-Hill, 1977
Buku Teks
Oxford University Press , 1994
Buku Teks
Pinter Publishers, 1993
Buku Teks
Ellis, Harry B., author
World Pub., 1965
Buku Teks
Richardson, Harry W., author
Program Perencanaan Nasional, 1975
Buku Teks