Sophie Laws, Caroline Harper, Nicola JOnes, Rachel Marcus
SAGE, 2013
Buku Teks
French, Sally, author
Butterworth-Heinemann, 2001
Buku Referensi
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McGraw-Hill, 1996
Buku Teks
Halford, D.R.C., author
Pan Books, 1971
Buku Teks
Oades, Lindsay G., author
Sage, 2019
Buku Teks