Oberschall, Anthony
Sage, 2004
Buku Teks
Midgley, James
Sage publications, 1995
Buku Teks
edited by Gove Hambidge ; foreword by Teodoro Moscosco, introd. by Paul G. Hoffman
Frederick A. Praeger, 1964
Buku Teks
edited by B.S. Hoyle
John Wiley & Sons, 1978
Buku Teks
Jayarajah, Carl
World Bank, 1996
Buku Teks