Keenan, Denis T., author
Pitman, 1970
Buku Teks
George, Edward F.
Sweet and Maxwell Ltd., 1970
Buku Teks
Sweet and Maxwell, 1975
Buku Teks
Bowers, John, 1956-, author
Blackstone Press, 1998
Buku Teks
Daniels, Kathy, author
Chartered Institute of Personnel and Development, 2012
Buku Teks