Bauer, P.T., author
Frederick A. Praeger, 1961
Buku Teks
compiled by CENDIT (Centre for Development of Instructional Technology); with the assistance of CAPART (Council for Advancement of People's Action and Rural Technology)
Sage, 1989
Buku Teks
Griffiths, Brian, author
Praeger , 1972
Buku Teks
Meier, Gerald M., author
Wiley, 1966
Buku Teks
edited by I. Livingstone
Penguin Books, 1971
Buku Teks