Croll, Elizabeth
International Labour Office, 1985
Buku Teks
United Nations Development Programme, 1980
Buku Teks
Whyte, Robert Orr
Westview Press, 1982
Buku Teks
N.V. Douglas, Chairman
A.R. Shearer, 1975
Buku Teks
Booth, Anne
Allen and Unwin, 1988
Buku Teks