Schippers, Frits
Technonet Asia, 1983
Buku Teks
Anderfelt, Ulf
Martinus Nijhoff, 1971
Buku Teks
edited by Roy Harrod
Martin Press, 1965
Buku Teks
edited by John M. Bennett and Robert E. Kalman
North Holland, 1981
Buku Teks
Okolie, Charles Chukwuma
Frederick A. Praeger, 1975
Buku Teks